0

Mechanical Behaviour & Testing of Materials Mcqs

Q:

Radiography don’t give ________

A) Thickness of material B) Hardness
C) Blow holes in casting D) Pores in weldment
 
Answer & Explanation Answer: B) Hardness

Explanation: Radiography is used for detecting internal defects mainly. Blow holes, voids and porosity are best examples.

View Answer Discuss

1385
Q:

Which property decreases on strain hardening?

A) Elastic modulus B) Percent elongation
C) Yield strength D) Hardness
 
Answer & Explanation Answer: B) Percent elongation

Explanation: Elastic modulus of metal increases slightly on strain hardening. Yield strength and hardness also improve. But it adversely decreases the percent elongation.

View Answer Discuss

823
Q:

The toughness of material depends on _____ and _____ of material.

A) Ductility, yield strength B) Ductility, tensile strength
C) Stiffness, tensile strength D) Hardness, yield strength
 
Answer & Explanation Answer: B) Ductility, tensile strength

Explanation: For a material to be tough, it should have a combination of good ductility and tensile strength. Materials which don’t undergo plastic deformation lacks toughness. For example, ceramics have poor toughness.

View Answer Discuss

777
Q:

What decreases fatigue strength?

A) Shot peening B) Case hardening
C) Inclusions D) Grain refinement
 
Answer & Explanation Answer: C) Inclusions

Explanation: Surface smoothness enhances fatigue strength of a material. Inclusions reduce surface smoothness. Shot peening, case hardening and grain refinement improve tensile strength and fatigue strength.

View Answer Discuss

758
Q:

If the Brinell hardness of a steel specimen is measured 149 HBN. What will be the UTS?

A) 431 MPa B) 514 MPa
C) 608 MPa D) 637 MPa
 
Answer & Explanation Answer: B) 514 MPa

Explanation: TS = 3.45 × HBN
TS = 3.45 × 149
= 514.05
~ 514 MPa
Here, HBN = Brinell hardness, TS = tensile strength of material in MPa.

View Answer Discuss

673
Q:

With an increase in strain rate, ductility ______ and tensile strength _____

A) Increases, increases B) Increases, decreases
C) Decreases, increases D) Decreases, decreases
 
Answer & Explanation Answer: C) Decreases, increases

Explanation: With an increase in strain rate, ductility of materials decreases. It is because material shows brittle behaviour. Tensile strength of material increases.

View Answer Discuss

582
Q:

Which process increases the hardness of the material?

A) Tempering B) Annealing
C) Quenching D) Over aging
 
Answer & Explanation Answer: C) Quenching

Explanation: Quenching of Steel gives martensite structure. It makes Steel harder by a factor of about four. Temperature, annealing and over aging decrease hardness of steel.

View Answer Discuss

557
Q:

With an increase in temperature, hardness of material _____ and ductility ______

A) Increases, increases B) Increases, decreases
C) Decreases, increases D) Decreases, decreases
 
Answer & Explanation Answer: C) Decreases, increases

Explanation: With an increase in temperature, material becomes softer. So hardness of material decreases. As a result, ductility increases.

View Answer Discuss

493