8/12/2019 Material Science Lecture

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Properties of materials

1. Chemical Propertiesrefer to the structure of a material and its formation from the elements.

a. compositionelemental or chemical components of the materials

b. corrosion resistanceability of the material to resists deterioration by chemical or

electromechanical reaction with its environment

c. crystal structureordered or repeating arrangement of atoms and molecules in a material

d. microstructurestructured of polished and etched material

e. stereo specificitytendency for polymers and molecular materials form with an ordered and 3-

dimensional

2. physical propertiesrefers to the interaction of materials with various form of energy

a. curie pointtemperature at which ferromagnetic materials can be no longer magnetized

b. densitymass/volume

c. dielectric strengthmaximum potential difference that an insulting material of given thickness can

be withstand for a specific time

d. electrical resistivityelectrical resistance of a material per unit length

e. heat distortion temp.temp. at which a polymer under a specific load shoes a specified amount of

deflection

f. melting pointmaterials liquefies on heating or solidifies on cooling

g, poissons ration ration of the transverse strain to the corresponding axial strainh. refractiveindexration of velocity of light in a vacuum to its velocity in another material

i. specific gravityration of mass or weight of a solid or a liquid to the mass or weight of an equal

volume of water

j. thermal conductivityrate of heat flow per unit time in a homogeneous material under steady state

conditions, per unit area

k. thermal expansionrate at which a material elongates when heated

3. mechanical propertiesmaterials that are displayed when a force is appliedto the materials

a. compressive strengthmaximum compressive stress that a material is capable of withstanding

b. creeppermanent strain under strain

c. creep strengthconstant, nominal stress that will cause a specified quantity of creepd. endurance limitmaximum stress below which material can theoretically endure an infinite

number of stress cylces

e. flexural strengthouter fiber stressed developed when a material is loaded as a simple supported

beam and deflected to certain value of strain

f. hardnessresistance of material to plastic deformation

g. modulus of elasticity

h. percent elongation

i. shear strengthstress required to fracture a shape In a cross sectional plane that parallel to the

force application

j. yield strengthstress at which material exhibits a specified deviation from proportionally of stress

and strain

4. dimensional propertiesmaterials that deals with its available size, shape, finish and tolerance

a. camberdeviation from edge straightness

b. laydirection of a predomination surface pattern

c. out of flatdeviation of a surface from a float plane

d. roughnessfinely spaced surface irregularities, the height, width, and the direction of which

establish

e. surface finishmicroscopic and macroscopic characteristics that describe a surface

f. wavinessa wave like variation from perfect surface