Mechanical Properties of Metals

Following condition represents onset of necking (a) εu = n (b) εu = 1-n (c) εu = 1+n(d) (d) εu = ln (1+n)

a

High elastic modulus in materials arises from (a) High strength of bonds (b) Weak bonds (c) combination of bonds (d) None

a

Change in elastic modulus for ordinary materials between 0K and melting point is (a) 10-20% increase (b) 10-20% decrease (c) 80-90% decrease (d) 80-90% increase

b

Time dependent recoverable deformation under load is called ____________ deformation. (a) Elastic (b) Anelastic (c) Elastic after-effect (d) Visco-elastic

b

Value of Poisson's ratio for ionic solids in the range of (a) 0.1 (b) 0.2 (c) 0.3 (d) 0.4

b

As compared with conventional stress-strain curve, the true stress-strain curve is (a) Above and right (b) Below and right (c) Above and left (d) Below and left

c

Bauschinger effect (a) Hysteresis loss during loading and unloading (b) Anelastic deformation (c) Dependence of yield stress on path and direction (d) None

c

Engineering stress-strain curve and True stress-strain curve are equal up to (a) Proportional limit (b) Elastic limit (c) Yeild point (d) Tensile strength point

c

If a material is subjected to two incremental true strains namely ε1 and ε2, then the total true strain is (a) ε1 * ε2 (b) ε1 - ε2 (c) ε1 + ε2 (d) ε1 / ε2

c

Plastic deformation results from the following (a) Slip (b) Twinning (c) Both (d) None

c

Time dependent permanent deformation is called ________________. (a) Plastic deformation (b) Elastic deformation (c) Creep (d) Anelastic deformation

c

Toughness of a material is equal to area under ____________ part of the stress-strain curve. (a) Elastic (b) Plastic (c) Both (d) None

c

True stress-strain curve need to be corrected after (a) Elastic limit (b) Yield limit (c) Tensile strength (d) no need to correct

c

von Mises and Tresca criteria give different yield stress for (a) Uni-axial stress (b) Balanced bi-axial stress (c) Pure shear stress (d) All

c

According to distortion-energy criterion, yielding occurs when (a) Distortion energy reaches a critical value (b) Second invariant of the stress deviator exceeded some critical value (c) Octahedral shear stress reaches a critical value (d) All

d

Figure-out the odd point in the following (a) Proportinal limit (b) Elastic limit (c) Yeild point (d) Fracture point

d

Hydrostatic stress results in the following (a) Linear strain (b) Shear strain (c) Both linear and shear strains (d) None

d

Shape of true stress-strain curve for a material depends on (a) Strain (b) Strain rate (c) Temperature (d) All

d