This set of Mechanical Behaviour Multiple Choice Questions & Answers (MCQs) focuses on “Creep Curve”.
1. Which metal is capable of maintaining its mechanical strength at a working temperature greater than 300 °C?
a) Pb
b) Zn
c) Fe
d) Sn
View Answer
Explanation: Metals except for Pb, Zn and Sn are capable of retaining their mechanical strength at a working temperature greater than 300 °C. This is due to Pb, Zn and Sn have low recrystallization temperature.
2. With an increase in temperature, the modulus of elasticity ____________
a) Increases
b) Decreases
c) Remains constant
d) First Increases, then decreases
View Answer
Explanation: With an increase in temperature, the modulus of elasticity decreases. Modulus of elasticity is related to bond length. It is a function of temperature.
3. With increases in temperature, yield strength __________ and tensile strength ___________
a) Increases, increases
b) Increases, decreases
c) Decreases, increases
d) Decreases, decreases
View Answer
Explanation: With an increase in temperature, yield strength, UTS and elastic modulus decreases. It is because of an increase in bond length.
4. Softening process dominates over hardening process in ___________ stage of creep.
a) Primary
b) Secondary
c) Tertiary
d) Quaternary
View Answer
Explanation: Softening process dominates over hardening process in the tertiary stage of creep. During this stage, recovery process predominates over strain hardening.
5. Stress rupture curves show the variation in stress as a function of ___________
a) Temperature
b) Time
c) Cycles
d) Notch depth
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Explanation: Log time versus log stress curves are known as stress rupture curves. These show variation in stress as a function of rupture time at constant temperatures.
6. The first stage of creep is also known as ___________ creep.
a) Transient
b) Viscous
c) Flow
d) Tertiary
View Answer
Explanation: First part of the creep curve is known as transient creep. Creep rate decreases with time in it.
7. Second stage of creep is also known as ___________ creep.
a) Primary
b) Secondary
c) Transient
d) Viscous
View Answer
Explanation: Second part of creep curve is with constant creep rate. It is known as viscous creep.
8. Viscous creep is represented by _________ constant in Andrade empirical equation.
a) β
b) k
c) ε
d) t
View Answer
Explanation: Viscous creep is known as k flow. Constant k represents this creep.
9. Transient creep is also known as _________ flow.
a) k
b) β
c) ε
d) t
View Answer
Explanation: Transient creep is also known as β flow. Constant β is used to represent this type of creep.
10. Andrade’s equation is only applicable to metals.
a) True
b) False
View Answer
Explanation: There are two different Andrade’s equations for transient and viscous creep. It is applicable to metals as well as some plastics.
11. k represents elongation per unit length at a constant rate.
a) True
b) False
View Answer
Explanation: k represents elongation per unit length at a constant rate. K is for viscous creep.
12. The most common creep rate corresponds to which the creep strength is specified is _________
a) 1% in 100 hrs
b) 1% in 1000 hrs
c) 1% in 10,000 hrs
d) 1% in 100,000 hrs
View Answer
Explanation: The most common creep rate corresponds to which the creep strength is specified is 1% in 10,000 hrs.
Sanfoundry Global Education & Learning Series – Mechanical Behaviour & Testing of Materials.
To practice all areas of Mechanical Behaviour & Testing of Materials, here is complete set of 1000+ Multiple Choice Questions and Answers.
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