research article sintering and hardness behavior of...

Research ArticleSintering and Hardness Behavior of Fe-Al2O3 Metal MatrixNanocomposites Prepared by Powder Metallurgy

Pallav Gupta1 Devendra Kumar1 Om Parkash1 and A K Jha2

1 Department of Ceramic Engineering Indian Institute of Technology (Banaras Hindu University) VaranasiUttar Pradesh 221005 India

2Department of Mechanical Engineering Indian Institute of Technology (Banaras Hindu University) VaranasiUttar Pradesh 221005 India

Correspondence should be addressed to Devendra Kumar devendraceriitbhuacin

Received 11 June 2014 Revised 11 August 2014 Accepted 20 August 2014 Published 10 September 2014

Academic Editor Suying Wei

Copyright copy 2014 Pallav Gupta et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

The present paper reports the investigations on sintering and hardness behavior of Fe-Al2O3Metal Matrix Nanocomposites

(MMNCs) prepared by Powder Metallurgy (PM) route with varying concentration of Al2O3(5ndash30wt) The MMNC specimens

for the present investigations were synthesized by ball milling followed by compaction and sintering in an inert atmosphere in thetemperature range of 900ndash1100∘C for 1ndash3 hours using Powder Metallurgy route Phase and microstructures of the specimens werecharacterized by XRD and SEM Reactive sintering takes place in these materials During sintering nano iron aluminate (FeAl

2O4)

phase forms Characterization was done by measuring density and hardness Results have been discussed critically to illustrate theeffect of various processing parameters on sintering and mechanical behavior It is expected that the results of these investigationswill be useful in developing Metal Matrix Nanocomposites (MMNCs) for typical industrial applications

1 Introduction

During the last few decades Metal Matrix Nanocomposites(MMNCs) have assumed an important position in industriesas these are being used successfully in a wide range of applica-tions due to improvement in the structural mechanical andelectrochemical properties respectively [1] There are severalroutes which are put forth by researchers throughout theglobe for the fabrication of the MMNC materials Amongstthem the stir casting and Powder Metallurgy (PM) are twoprominent routes which play a vital role in development ofquality MMNC products with improved structural mechan-ical and electrical properties [2] PM technique is usedmostly because it yields homogenous product using smallerheat treatment schedule [3] In this technology metal powderis taken as a startingmaterial and is mixed with ceramic rein-forcement in a suitable quantity [4] The mixture is com-pacted in a die and subsequently sintered in vacuum or inertatmosphere To a large extent the compaction of powderparticles and sintering conditions decide the properties of

MMNC so formed Another important factor which playsan important role in determining the properties of MMNCsis the particles size and particles size distribution [5 6] Aconsiderable amount of research work has already been doneon various technological aspects of MMNC using aluminumcopper and magnesium as matrices [7 8]

Chua et al has reported that for Mg-SiC composite useof smaller particles of SiC results in relatively higher elasticmodulus and tensile strength in a large number of thermalshock cycles [9] It has also been reported by Rahimian et al[8] that for Al-Al

2O3composites increase in the sintering

time at 600∘C from 60 to 90min leads to reduction in hard-ness from 67 to 59HB This is explained by the fact that onsintering for 90min at 600∘C grain growth occurred whichaccording to Hall-Petch theory leads to lower strength andhardness From the above discussion it can be seen that nosystematic attempt has been made for studying the sinteringand hardness behavior of iron based composites [10]

Recently structural mechanical and electrochemicalproperties of Fe-5Al

2O3metal matrix composite have been

Hindawi Publishing CorporationJournal of CompositesVolume 2014 Article ID 145973 10 pageshttpdxdoiorg1011552014145973

2 Journal of Composites

Table 1 Nomenclature of specimens

Sl no Sintering temperature(∘C)

Sintering time(h)

Specimen code5 Al2O3




1 900 1 5AFe900(1) 10AFe900(1) 20AFe900(1) 30AFe900(1)2 1000 1 5AFe1000(1) 10AFe1000(1) 20AFe1000(1) 30AFe1000(1)3 1100 1 5AFe1100(1) 10AFe1100(1) 20AFe1100(1) 30AFe1100(1)4 900 2 5AFe900(2) 10AFe900(2) 20AFe900(2) 30AFe900(2)5 1000 2 5AFe1000(2) 10AFe1000(2) 20AFe1000(2) 30AFe1000(2)6 1100 2 5AFe1100(2) 10AFe1100(2) 20AFe1100(2) 30AFe1100(2)7 900 3 5AFe900(3) 10AFe900(3) 20AFe900(3) 30AFe900(3)8 1000 3 5AFe1000(3) 10AFe1000(3) 20AFe1000(3) 30AFe1000(3)9 1100 3 5AFe1100(3) 10AFe1100(3) 20AFe1100(3) 30AFe1100(3)

investigated by us It was found that various properties ofthe nanocomposites vary with processing parameters andformation of the iron aluminate (FeAl

2O4) phase [11 12]

Wear behavior of the composites was studied at a fixed slidingvelocity of 4msec under a load of 05 10 and 20 Kg for1 hour of time interval respectively It was observed thatat low load the adhesive wear was more active whereasat high load the abrasive wear was more prominent [13]Various properties were found to improve on 5 addition ofAl2O3in iron matrix The major motivation in the present

case is the formation of the iron aluminate phase due toreactive sintering between iron and alumina particles Thepresent paper focuses on the study of various structural andmechanical characteristics by varying the amount of Al

2O3

reinforcement in the iron matrixIn the present paper results of a systematic study on

sintering and hardness behavior of Fe-Al2O3Metal Matrix

Nanocomposites (MMNCs) prepared by Powder Metallurgyhave been reported The experimental studies have beencarried out to correlate the effect of phase andmicrostructurewith mechanical properties It is expected that the outcomeof these experimental studies will be helpful in designingand developing Metal Matrix Nanocomposites for criticalindustrial applications

2 Experimental Work

21 Preparation of Test Specimens Electrolytic iron metalpowder having 995 purity and particle size in the range of49ndash58 microns and active aluminum oxide having particlessize in the range of 63ndash210 microns are used as starting mate-rials Composite selected for present investigation containsaluminum oxide (Al

2O3) in 5 10 20 and 30 by weight

Mixed powders were ball milled dry with the powder to ballratio of 1 2 using zirconia balls as the grinding and mixingmedia [14]Mixed powderswere compacted using a hydraulicpress under a constant load of 7 tons Green compactswere sintered in an argon atmosphere in the temperaturerange of 900∘C to 1100∘C for 1ndash3 hours After sintering thecompacts were machined on gap or extension type lathemachine Thereafter the surface of the specimens was pol-ished A nomenclature for example 5AFe900(1) is given to

each specimen Here 5 denotes the percentage of aluminumoxide A denotes aluminum oxide Fe denotes iron 900denote the sintering temperature in ∘C and 1 denotes time ofsintering in hour Sintered specimens are of 13mm diameterand 20mm height There were four systems and in eachsystem there were 9 specimens which were sintered for 3different temperatures and time Thus 36 specimens wereprepared for the present investigations Table 1 illustrates thenomenclature of specimens Specimen having 5 and 10of aluminum oxide showed good strength whereas specimenhaving 20 and 30 showed poor strength and was brittle innature The reason for this has been discussed in the resultsand discussion part of the paper

22 Experimental Measurements Phase determination wasdone by powder X-ray diffraction (XRD) using Rigaku Desk-top Miniflex II X-ray diffractometer employing Cu-K120572 radi-ation and Ni-filter Microstructure was studied using inspectS-50 FP 201712 scanning electron microscope Cylindri-cal specimens of 12mm diameter and 2mm thickness wereused for SEM studies Specimens were polished using var-ious grades of emery paper (10 20 30 and 40) andthen finally using diamond polish Nanocomposite speci-mens were etched with HCl for 20 sec and then washed withacetone

Density was determined from the mass and dimensions(ie radius and height) Hardness was measured on a Rock-well hardness tester using 1810158401015840 H scale steel ball indenterhaving a major loading capacity of 60Kg Reading of the Htype indenter was read on the red scale present on the dialgauge of the instrument

3 Results and Discussion

31 X-Ray Diffraction Representative XRD patterns of spec-imens with different Al

2O3contents sintered in the temper-

ature range of 900∘Cndash1100∘C are shown in Figures 1 2 3and 4 respectively Figure 1 shows XRD patterns of the speci-mens (a) 5AFe900(2) (b) 5AFe1000(2) and (c) 5AFe1100(2)respectively Diffraction peaks present in the specimen werematched with the XRD-JCPDS files of different compoundsIt was found that Fe Al

2O3 and FeAl

2O4phases were present

Journal of Composites 3

20 30 40 50 60 70 802000400060008000

10000

20 30 40 50 60 70 802000400060008000

10000

20 30 40 50 60 70 802000400060008000

10000

Fe (2

00)

Fe (1

10)

Fe (2

00)

Fe (1

10)

(b)

(c)

(a)

Fe (2

00)

Fe (1

10)

FeA

I 2O4

(311

)Fe

AI 2

O4

(311

)Fe

AI 2

O4

(311

)

AI 2

O3

(423

)A

I 2O3

(423

)A

I 2O3

(423

)

AI 2

O3

(400

)

2120579 (deg)

2120579 (deg)

2120579 (deg)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)

Figure 1 XRD of specimens (a) 5AFe900(2) (b) 5AFe1000(2) and(c) 5AFe1100(2) respectively

20 30 40 50 60 70 80

20 30 40 50 60 70 80

20 30 40 50 60 70 80

600800

10001200

Fe (2

00)

Fe (1

10)

Fe (1

10)

(a)

Fe (2

00)

Fe (1

10)

(b)

Fe (2

00)

(c)

FeA

I 2O4

(220

)

FeA

I 2O4

(311

)Fe

AI 2

O4

(311

)Fe

AI 2

O4

(311

)

AI 2

O3

(510

)A

I 2O

3(510

)A

I 2O3

(510

)

AI 2

O3

(422

)A

I 2O3

(422

)

2120579 (deg)

2120579 (deg)

2120579 (deg)

Inte

nsity

(cou

nts)

600800

10001200

Inte

nsity

(cou

nts)

600800

10001200

Inte

nsity

(cou

nts)

Figure 2 XRD of specimens (a) 10AFe900(2) (b) 10AFe1000(2)and (c) 10AFe1100(2) respectively

20 30 40 50 60 70 801000

1500

2000

20 30 40 50 60 70 801000

1500

2000

20 30 40 50 60 70 801000

1500

2000

Fe (1

10)

Fe (2

00)

(a)

Fe (1

10)

Fe (2

00)

(b)

Fe (2

00)

Fe (1

10)

(c)

FeA

I 2O

4(220

)Fe

AI 2

O4

(220

)

FeA

I 2O

4(311

)Fe

AI 2

O4

(311

)

FeA

I 2O

4(220

)

FeA

I 2O4

(311

)

AI 2

O3

(510

)A

I 2O

3(510

)A

I 2O

3(510

)

2120579 (deg)

2120579 (deg)

2120579 (deg)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)


20 30 40 50 60 70 80

1000

1500

2000

20 30 40 50 60 70 80

1000

1500

2000

20 30 40 50 60 70 80

1000

1500

2000Fe

(110

)

(a)

Fe (2

00)

Fe (1

10)

(b)

Fe (2

00)

Fe (1

10)

(c)

FeA

I 2O4

(220

)Fe

AI 2

O4

(220

)

FeA

I 2O

4(311

)Fe

AI 2

O4

(311

)A

I 2O

3(104

)

AI 2

O3

(510

)A

I 2O

3(510

)A

I 2O

3(510

)

AI 2

O3

(422

)

2120579 (deg)

2120579 (deg)

2120579 (deg)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)



in this nanocomposite specimen Specimens 5AFe900(2)and 5AFe1000(2) show presence of Fe Al

2O3 and FeAl

2O4

phases The number of peaks in the 5AFe1000(2) specimenwas more in comparison to specimen 5AFe900(2) Specimen5AFe1100(2) also showed presence of Fe Al

2O3 and FeAl

2O4

phases Formation of iron aluminate phase in the presentcase is due to the reactive sintering phenomenon XRD plotof 5 Al

2O3reinforced iron based metal matrix composite

shows traces of Al2O3and FeAl

2O4phases Amount of iron

aluminate phase depends upon the reaction between ironand alumina particles Since the percentage of alumina is lowtherefore iron aluminate phase formation is less and it is stilllesser for high temperature of sintering

Figure 2 showsXRDpattern of specimens (a) 10AFe900(2)(b) 10AFe1000(2) and (c) 10AFe1100(2) Specimen 10AFe900(2)shows the formation of Fe Al

2O3 and FeAl

2O4phases

respectively Similar to specimen 10AFe900(2) the other twospecimens that is 10AFe1000(2) and 10AFe1100(2) alsoshowed the presence of Fe Al

2O3 and FeAl

2O4phases The

iron aluminate phase is formed due to the reactive sinteringbetween the iron and alumina particles More amount ofAl2O3and less amount of FeAl

2O4phase were found in the

specimen 10AFe900(2) whereas a large amount of FeAl2O4

and small amount of Al2O3phase was found in the specimen

10AFe1100(2) It can be concluded from the above discussionthat as the sintering temperature increases the iron aluminatephase formation also increases

Figure 3 showsXRDpattern of specimens (a) 20AFe900(2)(b) 20AFe1000(2) and (c) 20AFe1100(2) Specimen20AFe900(2)showed the presence of iron (Fe) aluminum oxide (Al

2O3)

and iron aluminate (FeAl2O4) phases Similarly specimens

20AFe1000(2) and 20AFe1100(2) also showed presence of FeAl2O3 and FeAl

2O4phases Similar to the previous spec-

imens these specimens also showed the presence of ironaluminate phase which took place as a result of reactive sin-tering phenomenon between iron and alumina particles Itis also found that the amount of iron phase decreased andconsequently the amount of iron aluminate phase increasedas we increase the sintering temperature This change can beattributed by the fact that upon increasing the sintering tem-perature the rate of reaction between the iron and aluminaparticles increases thereby increasing the iron aluminatephase formation [15]

Figure 4 shows XRD patterns of the specimens (a)30AFe900(2) (b) 30AFe1000(2) and (c) 30AFe1100(2) respec-tively XRD pattern of 30AFe900(2) shows peaks of iron andaluminum oxide respectively Specimen 30AFe1000(2) and30AFe1100(2) shows presence of iron aluminum oxide andiron aluminate It can be seen from the XRD results that aswe increase the Al

2O3content as well as the sintering tem-

perature the amount of the iron aluminate phase increasessignificantly For lower percentage of reinforcement the reac-tion between iron and aluminum oxide particle is completeleading to small amount of iron aluminate phase But for highpercentage of Al

2O3(ie 30) formation of iron aluminate

phase was maximum in the specimen along with some tracesof aluminum oxide It is clear from XRD patterns that aswe increase the percentage of alumina the intensity of peaks

5 10 15 20 25 302

3

4

5

5 10 15 20 25 302

3

4

5

5 10 15 20 25 302

3

4

5

Den

sity

(gm

cc)

Den

sity

(gm

cc)

Den

sity

(gm

cc)

(a)

(b)

(c)

1100∘C (1h) 1100

∘C (2h) 1100∘C (3h)

1000∘C (1h) 1000

∘C (2h) 1000∘C (3h)

900∘C (1h) 900

∘C (2h) 900∘C (3h)

AI2O3 ()

AI2O3 ()

AI2O3 ()

Figure 5 Density versus Al2O3plots for the various specimens

due to Al2O3increases and so does the iron aluminate phase

formation

32 Density Figure 5(a) shows the plot between densityversus Al

2O3for the specimens sintered at 900∘C Speci-

men 5AFe900(1) shows a high value of density (433 gmcc)Specimens 10AFe900(1) 20AFe900(1) and 30AFe900(1)show a continuous decrease in the density values The den-sity for the specimens 10AFe900(1) 20AFe900(1) and30AFe900(1) was found to be 394 gmcc 361 gmcc and308 gmcc respectively Similarly specimen 5AFe900(2)showed a higher density (480 gmcc) in comparison withthe specimen 5AFe900(1) On increasing the percent of alu-mina (from 10ndash30) that is for specimens 10AFe900(2)20AFe900(2) and 30AFe900(2) the density values werefound to be 407 gmcc 364 gmcc and 303 gmcc respec-tively Density of the specimen 5AFe900(3) was found to beequal to that of 5AFe900(2) but higher than that of the spec-imen 5AFe900(1) Finally specimen 30AFe900(3) showedthe lowest density among all the three specimens that is5AFe900(3) 10AFe900(3) and 20AFe900(3) respectively

Figure 5(b) shows the density versus Al2O3plot for the

specimens sintered at 1000∘C Specimen 5AFe1000(1) showsdensity value of 478 gmcc Specimen 10AFe1000(1) showsthe density value of 393 gmcc specimen 20AFe1000(1)


(a) (b)

Figure 6 SEM images at 250x of (a) Fe powder and (b) Al2O3powder

shows the density value of 358 gmcc and specimen30AFe1000(1) shows density value of 306 gmcc On increas-ing the sintering time to 2 hours at the same sinteringtemperature specimen 5AFe1000(2) shows the density valueof 488 gmcc which is higher than that of the density ofspecimen 5AFe1000(1) 10AFe1000(2) shows the densityvalue of 425 gmcc and 20AFe1000(2) shows density valueof 379 gmcc Similarly specimen 30AFe1000(2) shows thedensity value of 316 gmcc After 2 hours of time interval thespecimens were sintered for a time interval of 3 h at 1000∘CSpecimen 5AFe1000(3) showed density value of 496 gmccSpecimens 10AFe1000(3) 20AFe1000(3) and 30AFe1000(3)showed density value of 450 gmcc 389 gmcc and 325 gmcc respectively

Figure 5(c) shows density versus Al2O3plot for the

specimens sintered at 1100∘C Specimen 5AFe1100(1) showsthe density value of 481 gmcc Subsequently specimens10AFe1100(1) 20AFe1100(1) and 30AFe1100(1) show the den-sity values of 447 gmcc 387 gmcc and 318 gmcc respec-tively The specimen when sintered for 2 hours yields thespecimens 5AFe1100(2) 10AFe1100(2) 20AFe1100(2) and30AFe1100(2) Density of these specimens was found to be490 gmcc 460 gmcc 393 gmcc and 324 gmcc respec-tively This shows that as we increase the amount of Al

2O3

the density values decrease significantly Among the spec-imens sintered for 3 hours specimen 5AFe1100(3) showsthe density value of 507 gmcc and specimens 10AFe1100(3)20AFe1100(3) and 30AFe1100(3) show the density values of498 gmcc 396 gmcc and 329 gmcc

The overall variation in the density values with thevariation in Al

2O3 sintering temperature and time can

be understood in the following manner Within the compo-sitional range the density value increases with the increase inthe sintering temperature as well as with the sintering timeOutside the compositional range that is for 10 20 and30 of the reinforcement of aluminum oxide the densityvalues decrease continuously This decrease in the densityvalues can be attributed to the increase in the volume fraction

of the iron aluminate phase formationThe theoretical densityof iron aluminate phase as calculated using the cell softwarewas found to be 423 gmcm3 Iron aluminate phase is brittlein nature and thus the density value decreases with increasein the aluminum oxide percentage

33 Scanning Electron Microscopy Figure 6(a) shows theSEM image of Fe powder at 250x which shows the homo-geneous sized particle of constituent phase The particlesize of the iron particle lies in the range of 50ndash55 micronsFigure 6(b) shows the SEM image of Al

2O3powder which

also shows the homogeneous sized particle of constituentphase It can be observed that the particle size of Al

2O3lies in

the range of 100ndash150 microns respectively Therefore it canbe concluded that the particle size of the powder taken fromelectron micrographs is in close proximity with that of themanufacturerrsquos specification

Figures 7 8 and 9 show the SEMof specimens 10AFe900(1)10AFe900(2) and 10AFe1100(1) at (a) 5000x and (b) 20000xmagnification respectivelyThemicrostructures are providedin such a sequence in order to study the effect of compositionsintering temperature and the sintering time respectivelyFigures 7(a) 8(a) and 9(a) show highly dense phase compos-ite structure containing negligible amount of porosity Thesemicrostructures show grains of Fe Al

2O3 and FeAl

2O4 The

dark black grains are of iron and white ones are of alumi-num oxide Remaining grey coloured grains are of iron alu-minate Figures 7(b) 8(b) and 9(b) show electron micro-graphs of the same specimens at 20000x magnification Thismicrostructure shows the micron and nanometer size grainsof iron aluminate phase The particle size lies in the range of14ndash135 nm respectively

Figures 10 11 and 12 show SEM of the specimens20AFe900(2) 20AFe1000(2) and 20AFe1100(2) specimensrespectively Figures 10(a) 11(a) and 12(a) show the scan-ning electron micrographs at 5000x The micrographs showthe presence of the particles of micron submicron andsome nanosize range particles of iron aluminate Since this


(a) (b)

Figure 7 SEM of 10AFe900(1) at (a) 5000x and (b) 20000x

(a) (b)


(a) (b)



(a)

Nano FeAI2O4

(b)


(a)

Nano FeAI2O4

(b)


(a)

Nano FeAI2O4

(b)



0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

900∘C (1h) 900

∘C (2h) 900∘C (3h)

AI2O3 ()

Figure 13 Hardness versus Al2O3for the specimens sintered at

900∘C

composition contains 20 aluminum oxide therefore forma-tion of FeAl

2O4was more as compared to the specimens

containing 10 of aluminum oxide reinforcementThereforein the present micrographs mostly the iron aluminate par-ticles are present Figures 10(b) 11(b) and 12(b) show themicrographs of the same specimens at 20000x All the threespecimens show nanosize particles of iron aluminate phase inthe range 70 to 100 nm

34 Hardness Figure 13 shows the variation of hardness withcontent of Al

2O3plot for the specimens sintered at 900∘C

Initially the hardness number for the specimen 5AFe900(1)was found to be 53 HRH Specimen 10AFe900(1) showed aslight increase in the hardness as compared to the specimen5AFe900(1) Its hardness number was found to be 55 HRHHardness of the specimen 20AFe900(1) is less than that of thespecimens 5AFe900(1) and 10AFe900(1) Hardness numberof the specimen 20AFe900(1) was found to be 23 HRHAmong specimens sintered at 900∘C for 2 hours specimen5AFe900(2) showed hardness value of 50 HRH which isless than the hardness number of specimen 5AFe900(1)10AFe900(2) showed a decrease in the hardness numberin comparison to specimen 5AFe900(2) 20AFe900(2) alsoshowed a lower hardness number The value of hardnessnumber for the specimen 10AFe900(2) and 20AFe900(2) wasfound to be 42 HRH and 17 HRH respectivelyThe specimen5AFe900(3) shows a hardness number of 40 specimen10AFe900(3) shows a hardness number almost the same asspecimen 5AFe900(3) and the specimen 20AFe900(3) showsa higher hardness number

Figure 14 shows hardness versus Al2O3reinforce-

ment plot for the specimens sintered at 1000∘C Specimen5AFe1000(1) shows a hardness number of 45 The hard-ness number of the specimen 10AFe1000(1) reduces a littlebit in comparison to the specimen 5AFe1000(1) Specimen

0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1000∘C (1h) 1000

∘C (2h) 1000∘C (3h)

AI2O3 ()


1000∘C

20AFe1000(1) shows a higher hardness number in com-parison to the specimens 5AFe1000(1) and 10AFe1000(1)Among the specimen sintered for a time interval of 2 hourat 1000∘C specimen 5AFe1000(2) shows hardness numberthe same as that of 5AFe1000(1) The hardness number ofspecimen 10AFe1000(2) is also the same as the hardnessnumber of the specimen 10AFe1000(1) and finally speci-men 20AFe1000(2) has highest hardness number Specimen5AFe1000(3) showed less hardness in comparison to thespecimens 5AFe1000(1) and 5AFe1000(2) On the other handspecimen 10AFe1000(3) showed higher hardness in com-parison to the specimen 10AFe1000(1) and 10AFe1000(2)respectively Specimen 20AFe1000(3) showed highest hard-ness number and it was found to be same as that of specimen20AFe1000(2)

Figure 15 shows the hardness versus Al2O3plot for the

specimens sintered at 1100∘C Specimen 5AFe1100(1) showedlow hardness being 38 HRH Specimen 10AFe1100(1) showedhardness number almost equal to specimen 5AFe1100(1)Specimen 20AFe1100(1) showed a higher hardness (72 HRH)in comparison to specimens 5AFe1100(1) and 10AFe1100(1)Specimen 5AFe1100(2) showed a higher hardness in compar-ison to specimen 5AFe1100(1) 10AFe1100(2) also shows anincrease in the hardness number of the specimen Its hard-ness number was found to be 54 HRH The hardness num-ber of the specimen 20AFe1100(2) was found to be 77 HRHOn increasing the sintering time for 3 hours specimens5AFe1100(3) 10AFe1100(3) and 20AFe1100(3) showed hard-ness number of 44 HRH 42 HRH and 79 HRH respec-tively It is quite interesting to note that the hardness valueof cast iron specimen was found to be 18 HRH which illus-trates that the hardness number of the formed nanocom-posites was much higher in comparison to the cast ironspecimen

Variation in the hardness number of the specimenswith respect to the sintering temperature and time can


0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1100∘C (1h) 1100

∘C (2h) 1100∘C (3h)

AI2O3 ()


1100∘C

be explained on the basis of the nature and type of thesintering in the composite for respective sintering timeTwo types of sintering behavior are observed in the presentnanocomposite system (i) solid state sintering betweeniron particles and (ii) reactive sintering between iron andaluminum oxide particles associated with the formation ofiron aluminate With first kind of sintering there will beno change in the fraction of ceramic reinforcement in thecomposite and metallic characteristics are enhanced due todensification resulting in the decrease in hardness numberwhereas with second kind of reactive sintering content ofaluminate phase that is ceramic phase increases resultingin an increase in the hardness number For lower sinteringtemperature reactive sintering rate is smaller than the solidstate sintering amongst Fe particles and hardness numberdecreases correspondingly with increasing sintering timeWith increasing sintering temperature reactive sintering rateincreases due to formation of ceramic FeAl

2O4nanopar-

ticles resulting in an increase in hardness number of thespecimen with increasing sintering temperature Further thevariation of the hardness number with Al

2O3can be

explained as follows for the sintering of the specimen doneat 900∘C for 1 h and 2 h of time interval the hardnessvalue first increases up to 10wt of Al

2O3and then it

decreases for 20wt For 3 h of time interval at 900∘C thehardness increases with the content of reinforcement It isdue to the reason that at this temperature and time intervaloptimum amount of iron aluminate phase formation hastaken place The hardness values for the specimen sinteredat 1000∘C and 1100∘C for different time intervals showed acontinuous increase in the hardness values up to 20 ofAl2O3reinforcement The hardness for the 30 reinforced

Al2O3could not be found due to brittleness of the speci-

men

4 Conclusions

A systematic study on sintering and hardness behavior ofFe-Al2O3Metal Matrix Nanocomposites (MMNC) prepared

by Powder Metallurgy has been reported in this paper Theexperimental results have been discussed critically and thefollowing important conclusions have been drawn

(i) Reactive sintering phenomena between iron and alu-mina leads to the formation of iron aluminate phase

(ii) SEM shows the formation of highly dense phasestructure with the presence of nano dispersion of ironaluminate phase

(iii) Density increases with the sintering temperature aswell as with the sintering time which is due to theformation of iron aluminate phase

(iv) Hardness value reduces for sintering carried out at900∘C for 1 and 2 hours whereas for rest of the casesit increases significantly

(v) It was found from the investigations that the ductilityis maintained in the specimens up to 10 of the alu-minum oxide dispersion after which the specimensbecome brittle in nature which is due to the increasein the formation of iron aluminate phase

It is expected that the results of these investigations will beuseful in developing technology for producing better qualityMMNC products at competitive rates

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgment

One of the authors Pallav Gupta thankfully acknowledges thefinancial support received from Council of Science and Tech-nology Uttar Pradesh (INDIA) under the Young ScientistsResearch Scheme

References

[1] D B Miracle ldquoMetal matrix compositesmdashfrom science totechnological significancerdquo Composites Science and Technologyvol 65 no 15-16 pp 2526ndash2540 2005

[2] P K Liaw D K Hsu N Yu N Miriyala V Saini and H JeongldquoInvestigation of metal and ceramic-matrix composites moduliexperiment and theoryrdquoActaMaterialia vol 44 no 5 pp 2101ndash2113 1996

[3] J M Torralba C E Da Costa and F Velasco ldquoPM aluminummatrix composites an overviewrdquo Journal ofMaterials ProcessingTechnology vol 133 no 1-2 pp 203ndash206 2003

[4] S Gorsse J P Chaminade and Y Le Petitcorps ldquoIn situ prepa-ration of titanium base composites reinforced by TiB singlecrystals using a powder metallurgy techniquerdquo Composites AApplied Science and Manufacturing vol 29 no 9-10 pp 1229ndash1234 1998


[5] Y G Wei ldquoParticulate size effects in the particle-reinforcedmetal-matrix compositesrdquo Acta Mechanica Sinica vol 17 no 1pp 45ndash58 2001

[6] S H Chen and T C Wang ldquoSize effects in the particle-rein-forced metal-matrix compositesrdquo Acta Mechanica vol 157 no1ndash4 pp 113ndash127 2002

[7] F Akhtar S J Askari K A Shah X Du and S Guo ldquoMicro-structure mechanical properties electrical conductivity andwear behavior of high volume TiC reinforced Cu-matrix com-positesrdquoMaterials Characterization vol 60 no 4 pp 327ndash3362009

[8] M Rahimian N Ehsani N Parvin andH R Baharvandi ldquoTheeffect of particle size sintering temperature and sintering timeon the properties of Al-Al

2O3composites made by powder

metallurgyrdquo Journal ofMaterials Processing Technology vol 209no 14 pp 5387ndash5393 2009

[9] B W Chua L Lu and M O Lai ldquoInfluence of SiC particleson mechanical properties of Mg based compositerdquo CompositeStructures vol 47 no 1-4 pp 595ndash601 1999

[10] E Pagounis M Talvitie and V K Lindroos ldquoInfluence of themetalceramic interface on the microstructure and mechanicalproperties ofHIPed iron-based compositesrdquoComposites Scienceand Technology vol 56 no 11 pp 1329ndash1337 1996

[11] P Gupta D Kumar O Parkash and A K Jha ldquoStructural andmechanical behavior of 5 Al

2O3reinforced Fe metal matrix

composites (MMC) produced by powder metallurgy (PM)routerdquo Bulletin of Materials Science vol 36 no 5 pp 859ndash8682013

[12] P Gupta D KumarM A Quraishi andO Parkash ldquoCorrosionbehavior of Al

2O3Fe metal matrix nanocomposites produced

by powder metallurgy techniquerdquo Advanced Science Engineer-ing and Medicine vol 5 no 4 pp 366ndash370 2013

[13] P Gupta D Kumar O Parkash and A K Jha ldquoEffect ofsintering onwear characteristics of Fe-Al

2O3metalmatrix com-

positesrdquo Proceedings of the Institution of Mechanical Engineers JJournal of Engineering Tribology vol 228 no 3 pp 362ndash3682014

[14] N Nemati R Khosroshahi M Emamy and A ZolriasateinldquoInvestigation of microstructure hardness and wear propertiesof Al-45wt Cu-TiC nanocomposites produced by mechani-cal millingrdquoMaterials and Design vol 32 no 7 pp 3718ndash37292011

[15] K Konopka and A Oziebło ldquoMicrostructure and the fracturetoughness of the Al

2O3-Fe compositesrdquo Materials Characteri-

zation vol 46 no 2-3 pp 125ndash129 2001

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


Table 1 Nomenclature of specimens

Sl no Sintering temperature(∘C)

Sintering time(h)





1 900 1 5AFe900(1) 10AFe900(1) 20AFe900(1) 30AFe900(1)2 1000 1 5AFe1000(1) 10AFe1000(1) 20AFe1000(1) 30AFe1000(1)3 1100 1 5AFe1100(1) 10AFe1100(1) 20AFe1100(1) 30AFe1100(1)4 900 2 5AFe900(2) 10AFe900(2) 20AFe900(2) 30AFe900(2)5 1000 2 5AFe1000(2) 10AFe1000(2) 20AFe1000(2) 30AFe1000(2)6 1100 2 5AFe1100(2) 10AFe1100(2) 20AFe1100(2) 30AFe1100(2)7 900 3 5AFe900(3) 10AFe900(3) 20AFe900(3) 30AFe900(3)8 1000 3 5AFe1000(3) 10AFe1000(3) 20AFe1000(3) 30AFe1000(3)9 1100 3 5AFe1100(3) 10AFe1100(3) 20AFe1100(3) 30AFe1100(3)

investigated by us It was found that various properties ofthe nanocomposites vary with processing parameters andformation of the iron aluminate (FeAl

2O4) phase [11 12]

Wear behavior of the composites was studied at a fixed slidingvelocity of 4msec under a load of 05 10 and 20 Kg for1 hour of time interval respectively It was observed thatat low load the adhesive wear was more active whereasat high load the abrasive wear was more prominent [13]Various properties were found to improve on 5 addition ofAl2O3in iron matrix The major motivation in the present

case is the formation of the iron aluminate phase due toreactive sintering between iron and alumina particles Thepresent paper focuses on the study of various structural andmechanical characteristics by varying the amount of Al

2O3

reinforcement in the iron matrixIn the present paper results of a systematic study on

sintering and hardness behavior of Fe-Al2O3Metal Matrix

Nanocomposites (MMNCs) prepared by Powder Metallurgyhave been reported The experimental studies have beencarried out to correlate the effect of phase andmicrostructurewith mechanical properties It is expected that the outcomeof these experimental studies will be helpful in designingand developing Metal Matrix Nanocomposites for criticalindustrial applications

2 Experimental Work

21 Preparation of Test Specimens Electrolytic iron metalpowder having 995 purity and particle size in the range of49ndash58 microns and active aluminum oxide having particlessize in the range of 63ndash210 microns are used as starting mate-rials Composite selected for present investigation containsaluminum oxide (Al

2O3) in 5 10 20 and 30 by weight

Mixed powders were ball milled dry with the powder to ballratio of 1 2 using zirconia balls as the grinding and mixingmedia [14]Mixed powderswere compacted using a hydraulicpress under a constant load of 7 tons Green compactswere sintered in an argon atmosphere in the temperaturerange of 900∘C to 1100∘C for 1ndash3 hours After sintering thecompacts were machined on gap or extension type lathemachine Thereafter the surface of the specimens was pol-ished A nomenclature for example 5AFe900(1) is given to

each specimen Here 5 denotes the percentage of aluminumoxide A denotes aluminum oxide Fe denotes iron 900denote the sintering temperature in ∘C and 1 denotes time ofsintering in hour Sintered specimens are of 13mm diameterand 20mm height There were four systems and in eachsystem there were 9 specimens which were sintered for 3different temperatures and time Thus 36 specimens wereprepared for the present investigations Table 1 illustrates thenomenclature of specimens Specimen having 5 and 10of aluminum oxide showed good strength whereas specimenhaving 20 and 30 showed poor strength and was brittle innature The reason for this has been discussed in the resultsand discussion part of the paper

22 Experimental Measurements Phase determination wasdone by powder X-ray diffraction (XRD) using Rigaku Desk-top Miniflex II X-ray diffractometer employing Cu-K120572 radi-ation and Ni-filter Microstructure was studied using inspectS-50 FP 201712 scanning electron microscope Cylindri-cal specimens of 12mm diameter and 2mm thickness wereused for SEM studies Specimens were polished using var-ious grades of emery paper (10 20 30 and 40) andthen finally using diamond polish Nanocomposite speci-mens were etched with HCl for 20 sec and then washed withacetone

Density was determined from the mass and dimensions(ie radius and height) Hardness was measured on a Rock-well hardness tester using 1810158401015840 H scale steel ball indenterhaving a major loading capacity of 60Kg Reading of the Htype indenter was read on the red scale present on the dialgauge of the instrument

3 Results and Discussion

31 X-Ray Diffraction Representative XRD patterns of spec-imens with different Al

2O3contents sintered in the temper-

ature range of 900∘Cndash1100∘C are shown in Figures 1 2 3and 4 respectively Figure 1 shows XRD patterns of the speci-mens (a) 5AFe900(2) (b) 5AFe1000(2) and (c) 5AFe1100(2)respectively Diffraction peaks present in the specimen werematched with the XRD-JCPDS files of different compoundsIt was found that Fe Al

2O3 and FeAl

2O4phases were present


20 30 40 50 60 70 802000400060008000

10000

20 30 40 50 60 70 802000400060008000

10000

20 30 40 50 60 70 802000400060008000

10000

Fe (2

00)

Fe (1

10)

Fe (2

00)

Fe (1

10)

(b)

(c)

(a)

Fe (2

00)

Fe (1

10)

FeA

I 2O4

(311

)Fe

AI 2

O4

(311

)Fe

AI 2

O4

(311

)

AI 2

O3

(423

)A

I 2O3

(423

)A

I 2O3

(423

)

AI 2

O3

(400

)

2120579 (deg)

2120579 (deg)

2120579 (deg)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)


20 30 40 50 60 70 80

20 30 40 50 60 70 80

20 30 40 50 60 70 80

600800

10001200

Fe (2

00)

Fe (1

10)

Fe (1

10)

(a)

Fe (2

00)

Fe (1

10)

(b)

Fe (2

00)

(c)

FeA

I 2O4

(220

)

FeA

I 2O4

(311

)Fe

AI 2

O4

(311

)Fe

AI 2

O4

(311

)

AI 2

O3

(510

)A

I 2O

3(510

)A

I 2O3

(510

)

AI 2

O3

(422

)A

I 2O3

(422

)

2120579 (deg)

2120579 (deg)

2120579 (deg)

Inte

nsity

(cou

nts)

600800

10001200

Inte

nsity

(cou

nts)

600800

10001200

Inte

nsity

(cou

nts)


20 30 40 50 60 70 801000

1500

2000

20 30 40 50 60 70 801000

1500

2000

20 30 40 50 60 70 801000

1500

2000

Fe (1

10)

Fe (2

00)

(a)

Fe (1

10)

Fe (2

00)

(b)

Fe (2

00)

Fe (1

10)

(c)

FeA

I 2O

4(220

)Fe

AI 2

O4

(220

)

FeA

I 2O

4(311

)Fe

AI 2

O4

(311

)

FeA

I 2O

4(220

)

FeA

I 2O4

(311

)

AI 2

O3

(510

)A

I 2O

3(510

)A

I 2O

3(510

)

2120579 (deg)

2120579 (deg)

2120579 (deg)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)


20 30 40 50 60 70 80

1000

1500

2000

20 30 40 50 60 70 80

1000

1500

2000

20 30 40 50 60 70 80

1000

1500

2000Fe

(110

)

(a)

Fe (2

00)

Fe (1

10)

(b)

Fe (2

00)

Fe (1

10)

(c)

FeA

I 2O4

(220

)Fe

AI 2

O4

(220

)

FeA

I 2O

4(311

)Fe

AI 2

O4

(311

)A

I 2O

3(104

)

AI 2

O3

(510

)A

I 2O

3(510

)A

I 2O

3(510

)

AI 2

O3

(422

)

2120579 (deg)

2120579 (deg)

2120579 (deg)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)




2O3 and FeAl

2O4


2O3 and FeAl

2O4







2O3 and FeAl

2O4phases


2O3 and FeAl

2O4phases The







2O3)










5 10 15 20 25 302

3

4

5

5 10 15 20 25 302

3

4

5

5 10 15 20 25 302

3

4

5

Den

sity

(gm

cc)

Den

sity

(gm

cc)

Den

sity

(gm

cc)

(a)

(b)

(c)

1100∘C (1h) 1100

∘C (2h) 1100∘C (3h)

1000∘C (1h) 1000

∘C (2h) 1000∘C (3h)

900∘C (1h) 900

∘C (2h) 900∘C (3h)

AI2O3 ()

AI2O3 ()

AI2O3 ()



formation







(a) (b)





2O3







2O3powder which


2O3lies in



2O3 and FeAl

2O4 The




(a) (b)


(a) (b)


(a) (b)



(a)

Nano FeAI2O4

(b)


(a)

Nano FeAI2O4

(b)


(a)

Nano FeAI2O4

(b)



0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

900∘C (1h) 900

∘C (2h) 900∘C (3h)

AI2O3 ()


900∘C









0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1000∘C (1h) 1000

∘C (2h) 1000∘C (3h)

AI2O3 ()


1000∘C






0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1100∘C (1h) 1100

∘C (2h) 1100∘C (3h)

AI2O3 ()


1100∘C


2O4nanopar-


2O3can be


2O3and then it



men

4 Conclusions











Acknowledgment


References





















2O3metalmatrix com-













CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




20 30 40 50 60 70 802000400060008000

10000

20 30 40 50 60 70 802000400060008000

10000

20 30 40 50 60 70 802000400060008000

10000

Fe (2

00)

Fe (1

10)

Fe (2

00)

Fe (1

10)

(b)

(c)

(a)

Fe (2

00)

Fe (1

10)

FeA

I 2O4

(311

)Fe

AI 2

O4

(311

)Fe

AI 2

O4

(311

)

AI 2

O3

(423

)A

I 2O3

(423

)A

I 2O3

(423

)

AI 2

O3

(400

)

2120579 (deg)

2120579 (deg)

2120579 (deg)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)


20 30 40 50 60 70 80

20 30 40 50 60 70 80

20 30 40 50 60 70 80

600800

10001200

Fe (2

00)

Fe (1

10)

Fe (1

10)

(a)

Fe (2

00)

Fe (1

10)

(b)

Fe (2

00)

(c)

FeA

I 2O4

(220

)

FeA

I 2O4

(311

)Fe

AI 2

O4

(311

)Fe

AI 2

O4

(311

)

AI 2

O3

(510

)A

I 2O

3(510

)A

I 2O3

(510

)

AI 2

O3

(422

)A

I 2O3

(422

)

2120579 (deg)

2120579 (deg)

2120579 (deg)

Inte

nsity

(cou

nts)

600800

10001200

Inte

nsity

(cou

nts)

600800

10001200

Inte

nsity

(cou

nts)


20 30 40 50 60 70 801000

1500

2000

20 30 40 50 60 70 801000

1500

2000

20 30 40 50 60 70 801000

1500

2000

Fe (1

10)

Fe (2

00)

(a)

Fe (1

10)

Fe (2

00)

(b)

Fe (2

00)

Fe (1

10)

(c)

FeA

I 2O

4(220

)Fe

AI 2

O4

(220

)

FeA

I 2O

4(311

)Fe

AI 2

O4

(311

)

FeA

I 2O

4(220

)

FeA

I 2O4

(311

)

AI 2

O3

(510

)A

I 2O

3(510

)A

I 2O

3(510

)

2120579 (deg)

2120579 (deg)

2120579 (deg)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)


20 30 40 50 60 70 80

1000

1500

2000

20 30 40 50 60 70 80

1000

1500

2000

20 30 40 50 60 70 80

1000

1500

2000Fe

(110

)

(a)

Fe (2

00)

Fe (1

10)

(b)

Fe (2

00)

Fe (1

10)

(c)

FeA

I 2O4

(220

)Fe

AI 2

O4

(220

)

FeA

I 2O

4(311

)Fe

AI 2

O4

(311

)A

I 2O

3(104

)

AI 2

O3

(510

)A

I 2O

3(510

)A

I 2O

3(510

)

AI 2

O3

(422

)

2120579 (deg)

2120579 (deg)

2120579 (deg)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)

Inte

nsity

(cou

nts)




2O3 and FeAl

2O4


2O3 and FeAl

2O4







2O3 and FeAl

2O4phases


2O3 and FeAl

2O4phases The







2O3)










5 10 15 20 25 302

3

4

5

5 10 15 20 25 302

3

4

5

5 10 15 20 25 302

3

4

5

Den

sity

(gm

cc)

Den

sity

(gm

cc)

Den

sity

(gm

cc)

(a)

(b)

(c)

1100∘C (1h) 1100

∘C (2h) 1100∘C (3h)

1000∘C (1h) 1000

∘C (2h) 1000∘C (3h)

900∘C (1h) 900

∘C (2h) 900∘C (3h)

AI2O3 ()

AI2O3 ()

AI2O3 ()



formation







(a) (b)





2O3







2O3powder which


2O3lies in



2O3 and FeAl

2O4 The




(a) (b)


(a) (b)


(a) (b)



(a)

Nano FeAI2O4

(b)


(a)

Nano FeAI2O4

(b)


(a)

Nano FeAI2O4

(b)



0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

900∘C (1h) 900

∘C (2h) 900∘C (3h)

AI2O3 ()


900∘C









0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1000∘C (1h) 1000

∘C (2h) 1000∘C (3h)

AI2O3 ()


1000∘C






0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1100∘C (1h) 1100

∘C (2h) 1100∘C (3h)

AI2O3 ()


1100∘C


2O4nanopar-


2O3can be


2O3and then it



men

4 Conclusions











Acknowledgment


References





















2O3metalmatrix com-













CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials





2O3 and FeAl

2O4


2O3 and FeAl

2O4







2O3 and FeAl

2O4phases


2O3 and FeAl

2O4phases The







2O3)










5 10 15 20 25 302

3

4

5

5 10 15 20 25 302

3

4

5

5 10 15 20 25 302

3

4

5

Den

sity

(gm

cc)

Den

sity

(gm

cc)

Den

sity

(gm

cc)

(a)

(b)

(c)

1100∘C (1h) 1100

∘C (2h) 1100∘C (3h)

1000∘C (1h) 1000

∘C (2h) 1000∘C (3h)

900∘C (1h) 900

∘C (2h) 900∘C (3h)

AI2O3 ()

AI2O3 ()

AI2O3 ()



formation







(a) (b)





2O3







2O3powder which


2O3lies in



2O3 and FeAl

2O4 The




(a) (b)


(a) (b)


(a) (b)



(a)

Nano FeAI2O4

(b)


(a)

Nano FeAI2O4

(b)


(a)

Nano FeAI2O4

(b)



0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

900∘C (1h) 900

∘C (2h) 900∘C (3h)

AI2O3 ()


900∘C









0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1000∘C (1h) 1000

∘C (2h) 1000∘C (3h)

AI2O3 ()


1000∘C






0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1100∘C (1h) 1100

∘C (2h) 1100∘C (3h)

AI2O3 ()


1100∘C


2O4nanopar-


2O3can be


2O3and then it



men

4 Conclusions











Acknowledgment


References





















2O3metalmatrix com-













CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




(a) (b)





2O3







2O3powder which


2O3lies in



2O3 and FeAl

2O4 The




(a) (b)


(a) (b)


(a) (b)



(a)

Nano FeAI2O4

(b)


(a)

Nano FeAI2O4

(b)


(a)

Nano FeAI2O4

(b)



0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

900∘C (1h) 900

∘C (2h) 900∘C (3h)

AI2O3 ()


900∘C









0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1000∘C (1h) 1000

∘C (2h) 1000∘C (3h)

AI2O3 ()


1000∘C






0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1100∘C (1h) 1100

∘C (2h) 1100∘C (3h)

AI2O3 ()


1100∘C


2O4nanopar-


2O3can be


2O3and then it



men

4 Conclusions











Acknowledgment


References





















2O3metalmatrix com-













CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




(a) (b)


(a) (b)


(a) (b)



(a)

Nano FeAI2O4

(b)


(a)

Nano FeAI2O4

(b)


(a)

Nano FeAI2O4

(b)



0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

900∘C (1h) 900

∘C (2h) 900∘C (3h)

AI2O3 ()


900∘C









0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1000∘C (1h) 1000

∘C (2h) 1000∘C (3h)

AI2O3 ()


1000∘C






0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1100∘C (1h) 1100

∘C (2h) 1100∘C (3h)

AI2O3 ()


1100∘C


2O4nanopar-


2O3can be


2O3and then it



men

4 Conclusions











Acknowledgment


References





















2O3metalmatrix com-













CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




(a)

Nano FeAI2O4

(b)


(a)

Nano FeAI2O4

(b)


(a)

Nano FeAI2O4

(b)



0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

900∘C (1h) 900

∘C (2h) 900∘C (3h)

AI2O3 ()


900∘C









0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1000∘C (1h) 1000

∘C (2h) 1000∘C (3h)

AI2O3 ()


1000∘C






0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1100∘C (1h) 1100

∘C (2h) 1100∘C (3h)

AI2O3 ()


1100∘C


2O4nanopar-


2O3can be


2O3and then it



men

4 Conclusions











Acknowledgment


References





















2O3metalmatrix com-













CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

900∘C (1h) 900

∘C (2h) 900∘C (3h)

AI2O3 ()


900∘C









0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1000∘C (1h) 1000

∘C (2h) 1000∘C (3h)

AI2O3 ()


1000∘C






0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1100∘C (1h) 1100

∘C (2h) 1100∘C (3h)

AI2O3 ()


1100∘C


2O4nanopar-


2O3can be


2O3and then it



men

4 Conclusions











Acknowledgment


References





















2O3metalmatrix com-













CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0 5 10 15 20 250

10

20

30

40

50

60

70

80

90

100

Har

dnes

s (H

RH)

1100∘C (1h) 1100

∘C (2h) 1100∘C (3h)

AI2O3 ()


1100∘C


2O4nanopar-


2O3can be


2O3and then it



men

4 Conclusions











Acknowledgment


References





















2O3metalmatrix com-













CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



















2O3metalmatrix com-













CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



research article sintering and hardness behavior of...

Documents