material science lab 1

8/9/2019 Material Science Lab 1

1/35

Tensile Testing Lab Report

By Anish Agrawal

Lab Partners (Group G):Son Trinh

Katy Hagerty

Daniel Margulis

MMS !"#Me$hani$s an% Materials Laboratory

Laboratory &'

Date o peri*ent: +an, !!- !"'#Sub*ission Date: +an, !.- !"'#


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Sub*itte% to : Dr, /agensABSTRACT

Thee

lasti$*o%ul

us-yiel%poi

nt-an%ulti*

atestren

LIST OF SYMBOLS


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gtho

'"'0steel-''

"1opper-23"

Brass-3"3'A

lu*inu*


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an% Te

4onwere%ete

r*ine%inuni

aialtensio

n, The5%o


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gbone

5spe$i*enge

o*etrywasus

e%sothatthe

sh

a

pef a

c


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ilu

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.


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Theel

asti$*o%ulu

so thespe$i

*enswas%ete

r*ine%th


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rough

thestress6s

traingrapha

n%wasinthee

rrorrang


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eo .7

8 orallthes

a*ples, Theu

lti*atestre

sswasals


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o oun

%tobeinthee

rrorrangeo

"86#"8,9en

thoughth


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eerro

rswerelarge

-it$anbeobs

er9e%thatth

estress6


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strai

nrelationsh

ips orthe*a

terialsinth

eeperi*


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entsw

ereobser9e%

e $ientlya

n%theelasti

$an%non6


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elast

i$regionwas

analy;e%asp

re%i$te%,

S?@?T?=@

A Area o9er whi$h or$e (lb) a$ts (in!) lasti$ *o%ulus (si)

> >or$e (lb)

(lo)i ?nitial %i*ension in %ire$tion i (in)

t Spe$i*en thi$ness (in)

$hart Cate o $hart %ispla$e*ent (in*in)


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%ispla$e*ent Cate o sa*ple %ispla$e*ent (in*in)

w Spe$i*en wi%th (in)

ε Strain

ε σ =0 Pre%i$te% strain at ;ero stress Eli 1hange in %i*ension in %ire$tion i (in)

Et rror in the spe$i*en thi$ness (in)

Ew rror in the wi%th (in)

σ ngineering stress (si)

σ y


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INTRODUCTION

The pri*ary obe$ti9e o this lab was to analy;e how se9eral %ierentspe$i*ens rea$te% un%er in$reasing uniaial loa%, Sa*ples '"'0 steel- ''"1opper- 23" Brass- 3"3' Alu*inu* an% Te4on were sube$te% to in$reasingaial loa%s using a *e$hani$al testing *a$hine, By re9iewing the respe$ti9e

stress 9s, strain graphs- orthese reasons- engineers %ene stress an% strain, Stress (engineering%enition) is gi9en by:

σ =F

A

Dene% in this *anner- the stress $an be thought o as a nor*ali;e% or$e,Strain (engineering %enition) is gi9en by:

εi =

E li(( lo

)i The strain $an be thought o as a nor*ali;e% %eor*ation,

/hile the relationship between the or$e an% %eor*ation %epen%s on thegeo*etry o the *aterial- the relationship between the stress an% strain isgeo*etry in%epen%ent, The relationship between stress an% strain is gi9en

by a si*plie% or* o Hooes Law ':σ = Eε (

Sin$e is in%epen%ent o geo*etry- it is oten thought o as a *aterial$onstant, Howe9er- is nown to %epen% on the $he*istry- stru$ture- an%te*perature o a *aterial, 1hange in any o these $hara$teristi$s *ust benown beore using a 5han%boo 9alue5 or the elasti$ *o%ulus,


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Hooes Law (Juation 2) pre%i$ts a linear relationship between thestrain an% the stress an% %es$ribes the elasti$ response o a *aterial, ?n*aterials where Hoos Law %es$ribes the stress6strain relationship- theelasti$ response is the %o*inant %eor*ation *e$hanis*, Howe9er- *any*aterials ehibit nonlinear beha9ior at higher le9els o stress, This nonlinear

beha9ior o$$urs when plasti$ity be$o*es the %o*inant %eor*ation*e$hanis*, Metals are nown to ehibit both elasti$ an% plasti$ responseregions, The transition ro* an elasti$ response to a plasti$ response o$$ursat a $riti$al point nown as the yiel% point (σ y), Sin$e a plasti$ response is$hara$teri;e% by per*anent %eor*ation (ben%ing)- the yiel% point is ani*portant $hara$teristi$ to now, ?n pra$ti$e- the yiel% point is the stresswhere the stress6strain beha9ior transor*s ro* a linear relationship to anon6linear relationship, The *ost $o**only use% *etho% to eperi*entally%eter*ine the yiel% point is the ",!8 oset *etho%, ?n this *etho%- a line is%rawn ro* the point ( σ N"- ε N",!8) parallel to the linear region o thestress6strain graph, The slope o this line is eJual to the elasti$ *o%ulus, Theyiel% point is then %eter*ine% as the interse$tion o this line with theeperi*ental %ata,

?n *aterials that ehibit a large plasti$ response- the %eor*ationten%s to lo$ali;e, 1ontinue% %eor*ation o$$urs only in this lo$al region- an%is nown as ne$ing, @e$ing begins at a $riti$al point nown as the ulti*atestress ( σ ult), Sin$e ailure o$$urs soon ater ne$ing begins- the ulti*atestress is an i*portant $hara$teristi$ to now, /hile *any eperi*ental testseist to %eter*ine the *e$hani$al properties- the si*plest is the tensiontest, A $on9enient geo*etry or a tensile test is the 5%ogbone5 geo*etry, ?nthis test geo*etry- one en% o the test spe$i*en is hel% e% while the otheren% is pulle% in uniaial tension $ollinear with the long ais o the sa*ple, The or$es throughout the sa*ple an% test *a$hine are $onstant- but thestress 9aries with $ross se$tional area,

INSTRUM"NT US"D#1) Digital Gauge (Mitutayo AbsoluteO Serial @o: '22!!!33)2) Tensile Gripper (1FCT?SO Serial @o: 33!!!.)3) Testing Ma$hine or Tensile Tests (ATSO Serial @o: ""6'#!6'!6"")4) QDogboneR shape% spe$i*en o '"'0 steel- ''" 1opper- 23" Brass-

3"3' Alu*inu*- Te4on

"$%"RIM"NTAL %ROC"DUR"

A tensile test sa*ple was *a$hine% ro* '"'0 steel sto$, The region o

*ini*u* $ross se$tion was *easure% an% re$or%e% by a %igital gauge(Serial @o: '22!!!33), This sa*ple was $la*pe% into an ATS Test Ma$hine(Serial @o: ""6'#!6'!6""), The sa*ple was hel% at a e% position with theother en% was %ispla$e% at a $onstant rate, A loa% $ell was use% to%eter*ine the or$e reJuire% to *aintain a $onstant %ispla$e*ent rate, Datawas $olle$te% on a DTS $o*puter sotware that *onitore% the or$e as aun$tion o %ispla$e*ent, The stress in the sa*ple at any or$e le9el $an be%eter*ine% ro* Juation ', The spe$i*en was sube$te% to a or$e until


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ailure, The abo9e *entione% pro$e%ures were peror*e% on ''" 1opper-23" Brass- 3"3' Alu*inu* an% Te4on seJuentially, /hile repla$ing ea$hspe$i*en- the resolution was obser9e% an% $onseJuently- the loa% was$hange% so that the initial negati9e %ata that was obser9e% %ue to thegripping o the spe$i*en was nullie%,

The rate o sa*ple %ispla$e*ent was ",' ","' in*in in the $ase o *etals

whereas it was ","' ",""' in*in, The elasti$ *o%ulus- yiel% point- an%

ulti*ate stress were %eter*ine% ro* the stress6strain plot,

R"SULTS AND DISCUSSION

The or$e6$hart %ispla$e*ent table (Appen%i A6) is $on9erte% into

stress an% strain tables to plot stress6strain $ur9es or all the spe$i*en,

>igure '6# $learly in%i$ates two regions o linear beha9ior in the low strainregion o the stress6strain graph, This beha9ior suggests that the sa*ple was9ery $o*pliant at low stress le9els- an% 9ery sti at high stress le9els,

Fnortunately- there is no stru$tural or $he*i$al reason why steel shoul%ehibit an in$reasing *o%ulus with in$reasing stress, Thereore- a *oreprobable eplanation is realign*ent an% rotation o the test ture in the low

stress (low or$e) region, Ce*e*ber- that the tet ture an% the sa*ple areun%er the sa*e applie% or$e, Fn%er these eperi*ental $on%itions- the*ost $o*pliant *e*ber will %o*inate the stress6strain beha9ior, /hile theture appears 9ery $o*pliant %uring realign*ent an% rotation- the ture

appears 9ery sti, The regression line while $al$ulating the *o%ulus o elasti$ity ha% a non6;ero 9alue, This non6;ero inter$ept suggests that thesa*ple *ust be $o*presse% in or%er to obtain ;ero strain, ?t shoul% be

note%- that this non6;ero inter$ept resulte% ro* the shit in strain 9alues %ueto realign*ent an% rotation o the ture- an% not %ue to per*anent%eor*ation or 9iolation o Hooes Law, The region o ture realign*entan% rotation $reates so*e %i$ulties in %eter*ining the yiel% point by the

",!8 oset *etho%, ?n the initial linear region- the *aority o the%eor*ation o$$urs in the ture an% not in the sa*ple, At the sa*e ti*e-so*e s*all a*ount o %eor*ation *ust o$$ur in the sa*ple sin$e the or$ein the sa*ple is greater than ;ero, The linear region use% to esti*ate the

elasti$ *o%ulus o the sa*ple- >igure - *ust be etrapolate% to ;ero stressto %eter*ine the onset o %eor*ation in the sa*ple,

Stiest *aterial was '"'0 steel be$ause the ulti*ate stress or '"'0steel was the highest, Liewise- '"'0 steel was the strongest *aterial aswell, Te4on was the *ost %u$tile sin$e the elongation 8 was the highest,


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>or uture eperi*ents- it woul% be i*portant to *ae sure that the negati9eor$e applie% while tightening the gripping o the *a$hine is nullie% beorethe or$e is applie% an% the resolution o the *a$hine is ept in *in% while%oing that, Also- it woul% be parti$ularly i*portant to *ae sure that there isno slipping o the *aterials an% the *aterial is pere$tly aligne%

9erti$ally,The ollowing table shows the *easure*ents o the %ierent*aterials use% %uring the spe$i*en,

Material Length (in,) /i%th (in,) Thi$ness (in,)

'"'0 Steel ",.3## ",'.3" ",'!2"

''" 1opper ",.07" ",'.2# ",'!2#

23" Brass ",.70" ",'.2# ",'!"

3"3' Alu*inu* ",.72" ",'.." ",'!."

Te4on ",.00" ",'.7# ",'!"

Table 1# Di&ensions o' te spei&en *se+

1,1- Steel

Fig*re 1# Stress.strain *r/e so0ing tpial iel+ bea/ior 'or 1,1-Steel 2 Stress (3) is so0n as a '*ntion o' strain (4)

Material%ropert o' Material

"5peri&entalRes*lt

Literat*re Res*lt 6Di7erent

'"'0 SteelMo%ulas o lasti$ity

(si) 7.,!3.''0!.7"" 6.78

Flti*ate Stress (si) '2#,"!#0 32,0 ''!8

Flti*ate Stain (inin) ",'7 ",""!' 70'8


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!8, Brass

Fig*re 1# Stress.strain *r/e so0ing tpial iel+ bea/ior 'or !8, Brass 2Stress (3) is so0n as a '*ntion o' strain (4)

Material %ropert o' Material "5peri&entalRes*lt Literat*reRes*lt 6Di7erent

23" BrassMo%ulas o lasti$ity

(si) !.#,!27"3.'""" 6.08

Flti*ate Stress (si) 30,.# 3',3 ''8

Flti*ate Stain (inin) ",!2! ","" #'728


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8,81 Al*&in*&

Fig*re 1# Stress.strain *r/e so0ing tpial iel+ bea/ior 'or 8,81Al*&in*& 2 Stress (3) is so0n as a '*ntion o' strain (4)


"5peri&entalRes*lt

Literat*reRes*lt

6Di7erent

3"3'Alu*inu*

Mo%ulus o lasti$ity(si) !!!

'"""" .70

Flti*ate Stress (si) ',73 # 7!

Flti*ate Stain (inin) ",'00 ",""# 6"770


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Te;on

Fig*re 1# Stress.strain *r/e so0ing tpial iel+ bea/ior 'or Te;on 2Stress (3) is so0n as a '*ntion o' strain (4)


"5peri&entalRes*lt

Literat*reRes*lt

6Di7erent

Te4onMo%ulas o lasti$ity

(si) ',!72'!! 6..8

Flti*ate Stress (si) 2,30. 2,37# "8

Flti*ate Stain (inin) !,0.. ","2"' .#!8


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CONCLUSIONS


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The elasti$ *o%ulus- yiel% point- an% ulti*ate strength o '"'0 steel- ''"1opper- 23" Brass- 3"3' Alu*inu* an% Te4on were %eter*ine% in uniaialtension, The 5%ogbone5 spe$i*en geo*etry was use% so that the shapefacilitate gripping the sample and failure in the central region. The elasti$ *o%ulus o thespe$i*ens was %eter*ine% through the stress6strain graph an% was in the

error range o .78 or all the sa*ples, The ulti*ate stress was also oun% tobe in the error range o "86#"8, 9en though the errors were large- it $an beobser9e% that the stress6strain relationships or the *aterials in theeperi*ents were obser9e% e$iently an% the elasti$ an% non6elasti$ regionwas analy;e% as pre%i$te%,A%%"NDI$ A: '"'0STL

1hannel 1ount: !Sa*ple 1ount: '''Start Ti*e: '!!!"'# 2:2:"' PMSa*pling ?nter9al: ",'

Sa*ple DateTi*e 1H" (in) 1H' (lbs)

'!2 2:'2,7 ",""! '!,!''! 2:'2,0 ",""! '!,!''!# 2:'2,. ",""! '!,!''!3 2:'," ",""! '!,!''!7 2:',' ",""! '!,!''!0 2:',! ",""! '!,!''!. 2:',2 ",""! '!,!''2" 2:', ",""! '7,".'2' 2:',# ",""! '!,!''2! 2:',3 ",""! '7,".

'22 2:',7 ",""! '!,!''2 2:',0 ",""! '!,!''2# 2:',. ",""! '7,".'23 2:'#," ",""! '!,!''27 2:'#,' ",""! '7,".'20 2:'#,! ",""! '7,".'2. 2:'#,2 ",""! '7,".'" 2:'#, ",""! '7,".'' 2:'#,# ",""! '7,".'! 2:'#,3 ",""! '7,".

'2 2:'#,7 6",""! '7,".' 2:'#,0 ",""! '!,!''# 2:'#,. ",""! '!,!''3 2:'3," ",""! '7,".'7 2:'3,' ",""! '7,".'0 2:'3,! ",""! '7,".'. 2:'3,2 ",""! '7,".


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'#" 2:'3, ",""! '7,".'#' 2:'3,# ",""! '!,!''#! 2:'3,3 ",""! '!,!''#2 2:'3,7 ",""! '7,".'# 2:'3,0 ",""! '7,".

'## 2:'3,. ",""! '7,".

A%%"NDI$ B: ''" 1opper

1hannel 1ount: !Sa*ple 1ount: '33'Start Ti*e: '!!!"'# 2:2.:7 PMSa*pling ?nter9al: ",'

Sa*ple DateTi*e 1H" (in) 1H' (lbs).! 2.:#3,# ",""! !',.70.2 2.:#3,3 ",""! !',.70. 2.:#3,7 ",""! !',.70.# 2.:#3,0 ",""! !',.70.3 2.:#3,. ",""! !',.70

.7 2.:#7," ",""7 !',.70

.0 2.:#7,' ",""7 !',.70

.. 2.:#7,! ",""7 !',.70'"" 2.:#7,2 ",""! !',.70'"' 2.:#7, ",""7 !',.70'"! 2.:#7,# ",""7 !3,03!'"2 2.:#7,3 ",""7 !3,03!'" 2.:#7,7 ",""7 7,2!3'"# 2.:#7,0 ",""7 !',.70'"3 2.:#7,. ",""7 !',.70

'"7 2.:#0," ",""! !',.70'"0 2.:#0,' ",""7 !',.70'". 2.:#0,! ",""7 !3,03!''" 2.:#0,2 ",""7 !',.70''' 2.:#0, ",""7 !',.70''! 2.:#0,# ",""7 !',.70''2 2.:#0,3 ",""7 !',.70


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'' 2.:#0,7 ",""7 !',.70''# 2.:#0,0 ",""7 !',.70''3 2.:#0,. ",""7 !',.70''7 2.:#.," ",""! !3,03!''0 2.:#.,' ",""7 !3,03!

''. 2.:#.,! ",""7 !3,03!'!" 2.:#.,2 ",""7 !3,03!'!' 2.:#., ",""7 !3,03!'!! 2.:#.,# ",""7 !3,03!'!2 2.:#.,3 ",""! !3,03!'! 2.:#.,7 ",""7 !3,03!'!# 2.:#.,0 ",""7 !3,03!


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A%%"NDI$ D# 3"3' Alu*inu*

1hannel 1ount: !Sa*ple 1ount: '!"Start Ti*e: '!!!"'# 2:#':'# PMSa*pling ?nter9al: ",'

Sa*ple DateTi*e 1H" (in) 1H' (lbs)3" #':!',2 ",""! 7,2!33' #':!', ",""! 7,2!33! #':!',# ",""! 7,2!332 #':!',3 ",""! 7,2!33 #':!',7 ",""! '!,!'3# #':!',0 ",""! 7,2!333 #':!',. ",""! '!,!'37 #':!!," ",""! 7,2!330 #':!!,' ",""! '!,!'

3. #':!!,! ",""! '!,!'7" #':!!,2 ",""! '!,!'7' #':!!, ",""! '!,!'7! #':!!,# ",""! '!,!'72 #':!!,3 ",""! '7,".7 #':!!,7 ",""! '!,!'7# #':!!,0 ",""! '7,".73 #':!!,. ",""! '7,".77 #':!2," ",""! '7,".70 #':!2,' ",""! '7,".

7. #':!2,! ",""! !',.700" #':!2,2 ",""! !',.700' #':!2, ",""! !',.700! #':!2,# ",""! !',.7002 #':!2,3 ",""! !',.700 #':!2,7 ",""! !',.700# #':!2,0 ",""! !',.7003 #':!2,. ",""! !',.70


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07 #':!," ",""! !3,03!00 #':!,' ",""! !',.700. #':!,! 6",""! !3,03!." #':!,2 ",""! !3,03!

A%%"NDI$ "# Te4on

1hannel 1ount: !Sa*ple 1ount: '7#7Start Ti*e: '!!!"'# :"":0 PMSa*pling ?nter9al: ",'

Sa*ple DateTi*e 1H" (in) 1H' (lbs)


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!3 "":#',! ",""! !,!!7 "":#',2 ",""! !,!!0 "":#', ",""! 7,2!3!. "":#',# ",""7 '!,!'2" "":#',3 ",""7 '!,!'

2' "":#',7 ",""! '!,!'2! "":#',0 ",""7 '!,!'22 "":#',. ","'! '7,".2 "":#!," ","'! '7,".2# "":#!,' ","'! '7,".23 "":#!,! ","'! !',.7027 "":#!,2 ","!! !',.7020 "":#!, ","!! !',.702. "":#!,# ","!! !3,03!" "":#!,3 ","!! !',.70

' "":#!,7 ","!7 !3,03!! "":#!,0 ","!7 !3,03!2 "":#!,. ","!7 !3,03! "":#2," ","!7 !3,03!# "":#2,' ","2! !3,03!3 "":#2,! ","2! 2',737 "":#2,2 ","2! 2',730 "":#2, ","2! !3,03!. "":#2,# ","2! 2',73#" "":#2,3 ","27 2',73

#' "":#2,7 ","2! 2',73#! "":#2,0 ","2! 2',73#2 "":#2,. ","3 2',73# "":#," ","3 2',73## "":#,' ","3 23,32#3 "":#,! ","3 2',73

Re'erenes#

1) Har%ness,- =* Brinell- an% 1on9erte% >ro* Bri, A?S? '"'0 Steel- 1ol%Drawn (n,%,): n, pag, /eb,

URL:http://ametme.mnsu.edu/userfilesshared/DATA_ACQUISITION/mts/MaterialData/

MaterialData_68!"##8C$ldDra%n.pdf


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2) 1opper 1DA ''" Material Property Data Sheet,5 Elgin Fastener Group,@,p,- n,%, /eb, !. +an, !"'#,

FCL: http://el&infasteners.'$m/res$ur'es/ra%"material"te'hni'al"data"spe'ifi'ati$ns/'$pper"'da"##"material"pr$pert("data"sheet/

3) Gui%e to Buying Brass =nline U =nline Metals Gui%e to Sele$ting Metalsor


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#ns: $his is because dogbone! shapes facilitate gripping the sample and failure in the centralregion.

3) %omplete the table below.

a. &ind the 'oungs modulus (si)* ultimate tensile stress (si)* and percent

elongation of each material listed in the +pecimen ,reparation! section abo-e.i-e a reference for all of your -alues (web addresses are fine).

b. /ndicate whether you expect the material to be ductile or brittle. i-e

definitions below for ductile and brittle material.0uctile Material that e3perien'es plasti' def$rmati$n that has )een

sustained at fra'ture is termed du'tile.

2rittle Material that e3perien'es 4er( little $r n$ plasti' def$rmati$nup$n fra'ture is termed )rittle

c. 0etermine the ultimate tensile force (lbs) of each material assuming that thedogbone specimen is 134 inch wide and 135 inch thic. What is the minimum

capacity load cell that we will need for our experiments"

# 1367 inch7

Material 'oungs Ultimate 8 Reference0uctileor Ultimate

modulus stress 9longation 2rittle force

(si) (si) (lbs)

115 +teel 7;8 http:33amet?

me.mnsu.edu3userfilessha

0uctile 1;;6.


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red30#$#@#%AU/+/$/B C3mts3Daterial0ata3Date

rial0ata@=5;?

115%old0rawn.pdf

11 18

http:33elginfasteners.com3resources3raw?material?technical?

data?specifications3copper?

cda?11?material?property?

data?sheet3 0uctile ;;=.;

%opper

6= 2rass 14 =1.= 768

http:33www.onlinemetals.

com3productguides3brass

guide.cfm 0uctile 1;7>

==1

#luminum 1 4> 178

http:33asm.matweb.com3s

earch3+pecificDaterial.as

p"bassnumD#==1t= 0uctile 14=.7>

$eflon >5 ? 7=1 1.4> E =.74 > ? => 8

http:33www.bearingwors.com3content@files3pdf3ret

ainers3,$&9

87datasheet.pdf 0uctile 4>.6?1;>

material science lab 1

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