Mechanical Properties of Materials Flashcards
Brittleness is
Tendency to fracture even at very small loads.
Creep is
deformation of a material at elevated temperatures
Ductility is
how much a material can deform without sustaining internal damage
Fatigue is
weakening of a material due to repeated (cyclic) loading
Hardness is
ability to resist permanent change in shape due to external load (applied)
Plasticity is
ability of a material to stay deformed after external; forces are removed (eg. paper clip)
Resilience is
ability to absorb energy and resist soft and impact loading
Stiffness is
ability to resist deformation as loading continues
Toughness is
ability of a material to resist fracture before failure.
What Stacking sequence does FCC have?
ABCABCABC
What Stacking sequence does HCP have?
ABABABAB
What are the 3 main crystal structures we studied this semester?
BCC, FCC, HCP
what are the zones on a conventional true stress-strain diagram from right to left?
elastic behavior, plastic(yielding, strain hardening,necking) behavior.
How do you measure elastic deformation?
Hookes law and Poisson’s ratio
What are the three tests used to measured material Hardness?
Rockwell, Brinell and Vickers.
what are the test parameters for hardness testing?
Load, Indenter, Dwell time.
what does the letter E represent?
Elastic Modulus or Young’s modulus
What does the letter G represent?
Shear Modulus
what is poisson’s ratio?
poisons ratio v is defined as the ratio of the lateral and axial strains.
What does this formula give for isotropic materials? E=2G(1+v)
it gives a relationship between shear and elastic moduli. if one is known then the other can be approximated.
what is yield strength?
the bend between the elastic and plastic regions. (basically where the elastic limit is reached and plastic deformation begins).
what is tensile strength?
it is the maximum stress at a point on the engineering stress strain curve. it is the maximum stress that can be sustained by a structure in tension. if this stress is applied and maintained, fracture will result.
what is %EL?
% elongation
what is %RA?
% Reduction in Area
the hotter the material is the more brittle it is
False
