High Temperature deformation - Mechanical Behaviour of Materials - Metallurgical Engineering Previous Year Questions

1

2008 · Metallurgical Engineering · Mechanical Behaviour of Materials · High Temperature deformation

Metallurgical Engineering (MT) 2008

Match the mechanical behaviour in Group 1 with the terms in Group 2

A

Check answer

Open complete paper

2

2014 · Metallurgical Engineering · Mechanical Behaviour of Materials · High Temperature deformation

Metallurgical Engineering (MT) 2014

Which one of the following microstructures of a Ni-base superalloy imparts the highest creep resistance?

A

Fine grained equiaxed

B

Coarse grained equiaxed

C

Columnar

D

Single crystal

Open complete paper

3

2016 · Metallurgical Engineering · Mechanical Behaviour of Materials · High Temperature deformation

Metallurgical Engineering (MT) 2016

Creep resistance decreases due to

A

Small grain size

B

Fine dispersoid size

C

Low stacking fault energy

D

High melting point

Check answer

Open complete paper

4

2018 · Metallurgical Engineering · Mechanical Behaviour of Materials · High Temperature deformation

Metallurgical Engineering (MT) 2018

Determine the correctness (or otherwise) of the following Assertion [A] and the Reason [R]

Assertion [A]: For a material exhibiting Coble creep, a reduction in grain size results in a significant increase in creep rate
Reason [R]: Grain boundaries act as a barrier to motion of dislocations

A

Both [A] and [R] are true and [R] is the correct reason for [A]

B

Both [A] and [R] are true, but [R] is not the correct reason for [A]

C

Both [A] and [R] are false

D

[A] is true but [R] is false

Open complete paper

5

2019 · Metallurgical Engineering · Mechanical Behaviour of Materials · High Temperature deformation

Metallurgical Engineering (MT) 2019

In a tensile creep test of a metal, Nabarro-Herring mechanism is favored over Coble mechanism for ____________.

A

larger grain size and lower temperature

B

smaller grain size and higher temperature

C

larger grain size and higher temperature

D

smaller grain size and lower temperature

Open complete paper

6

2020 · Metallurgical Engineering · Mechanical Behaviour of Materials · High Temperature deformation

Metallurgical Engineering (MT) 2020

Determine the correctness or otherwise of the following Assertion [a] and the Reason [r]
Assertion [a]: Low-alloy steels used for medium-temperature creep resistance often have additions of strong carbide-forming elements.
Reason [r]: During creep deformation, the particles with higher misfit with the matrix, lose coherency.

A

Both [a] and [r] are true and [r] is the correct reason for [a].

B

Both [a] and [r] are true but [r] is not the correct reason for [a].

C

Both [a] and [r] are false.

D

[a] is true but [r] is false.

Open complete paper

7

2020 · Metallurgical Engineering · Mechanical Behaviour of Materials · High Temperature deformation

Metallurgical Engineering (MT) 2020

The steady state creep rate of a material increases by a factor of 20 when the temperature is increased from 890 K to 980 K. The creep rate at a temperature of ______ K (round off to the nearest integer) will be 5 times the creep rate at 890 K.

Check answer

Open complete paper

8

2021 · Metallurgical Engineering · Mechanical Behaviour of Materials · High Temperature deformation

Metallurgical Engineering (MT) 2021

Which one of the following is FALSE for creep deformation?

A

The minimum creep rate is obtained in the primary stage (stage I).

B

Creep resistance decreases with decrease in grain size.

C

Coble creep occurs via grain boundary diffusion.

D

Nabarro-Herring creep occurs via lattice diffusion.

Open complete paper

9

2022 · Metallurgical Engineering · Mechanical Behaviour of Materials · High Temperature deformation

Metallurgical Engineering (MT) 2022

While designing a material for high temperature application, which of the following characteristic(s)/attribute(s) is(are) desirable for achieving better creep resistance?

A

Fine grain size

B

FCC crystal structure

C

High melting point

D

Cold worked microstructure

Check answer

Open complete paper

10

2023 · Metallurgical Engineering · Mechanical Behaviour of Materials · High Temperature deformation

Metallurgical Engineering (MT) 2023

The mechanism of creep for a single crystal as depicted in the schematic is

A

Nabarro-Herring creep

B

Grain boundary sliding

C

Dislocation creep

D

Coble creep

Open complete paper

11

2024 · Metallurgical Engineering · Mechanical Behaviour of Materials · High Temperature deformation

Metallurgical Engineering (MT) 2024

A creep test of a pure polycrystalline metal is performed in tension and the creep strain rate is observed to decrease during the primary stage. The creep mechanism is later determined to be dislocation-climb-controlled. The observed decrease in creep strain rate is/are due to

A

an increase in dislocation density.

B

grain growth.

C

a decrease in the dislocation density.

D

an increase in the cross-sectional area of the sample.

Open complete paper

12

2025 · Metallurgical Engineering · Mechanical Behaviour of Materials · High Temperature deformation

Metallurgical Engineering (MT) 2025

In polycrystalline Ni, Nabarro-Herring diffusion creep was found to be the rate controlling creep mechanism at a certain temperature.
At that temperature, if the steady state strain rate is 10^-8 s^-1 at a stress of 10 MPa, the steady state strain rate of 10^-9 s^-1 will be obtained at a stress value of ____ MPa (in integer).
Assume that the same creep mechanism is rate controlling during the creep deformation.

Check answer

Open complete paper

13

2026 · Metallurgical Engineering · Mechanical Behaviour of Materials · High Temperature deformation

Metallurgical Engineering (MT) 2026

Deformation mechanism map of a given material is used for determining which one of the following properties?

A

Fatigue strength

B

Creep rate

C

Tensile strength

D

Impact toughness

Open complete paper