Mechanical Metallurgy Mid - I, September - 2014

1.Which of the following is mainly a measure of plasticity and density?
  • Scratch hardness
  • Abrasive hardness
  • Indentation hardness
  • Rebound hardness
Answer: C
2.The total energy absorbed by the material prior to its fracture is termed as
  • Stiffness
  • Resilience
  • Toughness
  • Elongation
Answer: C
3.The following property cannot be changed by heat treatment
  • Toughness
  • Resilience
  • Young’s modulus
  • Hardness
Answer: C
4.High value of resilience is necessary for the components like
  • Handles
  • Shock absorbers
  • Windows
  • Bars and rods
Answer: B
5.Notch increases the tendency for brittle fracture by the following means:
  • By producing high local stress
  • by introducing bi-axial state of stresses
  • By producing low strain hardening
  • By producing very low stresses.
Answer: A
6.The best way to compare the mechanical properties of different materials at various temperatures in terms of
  • Flow stress
  • Creep
  • Fracture
  • Homologous temperature
Answer: D
7.Slip occurs in FCC lattice on the ___________planes.
  • {100}
  • {111}
  • {101}
  • {001}
Answer: B
8.The combination of two partial dislocations is known as
  • Positive dislocation
  • Extended dislocation
  • Negative dislocation
  • Unit dislocation
Answer: B
9.The scratch hardness value for martensite in terms of Moh’s scales.
  • 7
  • 2
  • 1
  • 4
Answer: A
10.In Rockwell hardness test, the hardened steel is tested on
  • C scale with 60kg major load
  • C scale with 150kg major load
  • A scale with 20kg major load
  • A scale with 60kg major load
Answer: B
11.If the extra plane of atoms is above the line defect then it is called as _______________dislocation.
Answer: positive
12.__________________ type of defect increases the kinetics of diffusion and phase transformations.
Answer: vacancies
13.The values of tensile stress required to be applied to start the slip depends on _______________ of the slip plane with respect to the applied stress and slip direction.
Answer: orientation
14.The relative hardness calculated by using Brinell principles is called as ____________.
Answer: poldi hardness
15.The ability of a material to exhibit large plastic deformation prior to fracture under compressive loading conditions is called as _______________.
Answer: malleability
16.Dislocation climb is not possible in ____________________type of dislocation.
Answer: screw
17.________________ is a sharp break in the dislocation line which remain in the slip plane.
Answer: kink
18.__________ fracture occurs as a result of extensive slip on the active slip planes.
Answer: shear
19.The sensitivity of the fracture of brittle solids to surface conditions is termed as ___________.
Answer: Joffe effect
20._____________________ suggested that the Griffith’s equation would be made more compatible with brittle fracture in metals by inclusion of a term plastic work required to extend the crack wall.
Answer: Orowan