Boundaries in Single Phase Solids MCQ

Test your knowledge with important Boundaries in Single Phase Solids MCQ and their applications. These MCQs are beneficial for competitive exams too. Explore 30 + more Boundaries in Single Phase Solids MCQs at Bissoy

• If unit area of grain boundary advances a distance 4mm, the number of moles of material that enter in the grain B is 4* (1/ 8(mm3/mol)) and the free energy released is given by_______ (ΔG =10kJ/mol)
  ক

  5 kJ/mol*mm2

  খ

  20 kJ/mol*mm2

  গ

  10 kJ/mol*mm2

  ঘ

  40 kJ/mol*mm2
• On heating to a sufficiently high temperature, what happens to the new grains?
  ক

  They fall off

  খ

  They disperse

  গ

  Velocity decreases

  ঘ

  They grow and nucleate
• It is possible that the higher mobility of special grain boundaries plays a role in the development of recrystallization textures.
  ক

  True

  খ

  False
• For low mole fractions of solute in the matrix 0.5 (Xo), the boundary solute concentration Xb (in 10-12) is given by_____ (ΔG =105kJ/Mol, T =505K)
  ক

  6.94

  খ

  7.94

  গ

  6.14

  ঘ

  9.80
• During recrystallization, the boundaries between the new strain-free grains and the original deformed grains are acted on by a force ΔG /V where, in this case, ΔG is due to the difference in dislocation strain energy between the two grains.
  ক

  False

  খ

  True
• Calculate the chemical potential if the molar volume is given as 5 mm3/mol? (Given the value of radius as 4mm and the interfacial energy γ is 8 kJ/mm2?
  ক

  10

  খ

  20

  গ

  24

  ঘ

  22
• Calculate the pulling force F, if the chemical potential and the molar volume is given as respectively?
  ক

  ΔG-V

  খ

  ΔG+V

  গ

  ΔG/V

  ঘ

  ΔG*V
• Under which of the following circumstances the grain boundary behaves as a thin soap film?
  ক

  When the boundary energy is dependent on the orientation

  খ

  When boundary energy is 0

  গ

  When the torque is greater than zero

  ঘ

  When the boundary energy is independent on the orientation
• What will be the torque acting on the boundary if the boundary happens to be at the orientation of a cusp in the free energy?
  ক

  500 Nm

  খ

  Greater than 500 Nm

  গ

  Less than 500 Nm

  ঘ

  Zero
• What is the need for a grain boundary in an annealed material?
  ক

  To control the grain size

  খ

  To maintain its shape

  গ

  It can produce a stable equilibrium at the grain edges

  ঘ

  During annealing it produce a metastable equilibrium at the grain boundary intersections
• When two grains meet in a plane it is known as _____
  ক

  Grain corner

  খ

  Grain boundary

  গ

  Grain edge

  ঘ

  Grain center
• When the two grains are related by a rotation about a <110> axis, there are several large-angle orientations which have significantly lower energies than the random boundaries.
  ক

  True

  খ

  False
• When the two grains are related by a rotation about a <100> axis, it can be seen that most high-angle boundaries have _____
  ক

  Almost same energy

  খ

  Different energy

  গ

  Highly ordered structure

  ঘ

  Nothing can be said about their energies
• When the boundary moves the solute atoms migrate along with the boundary and exert a drag that reduces the boundary velocity. The magnitude of the drag will depend on ______
  ক

  Shape of the boundary

  খ

  Texture

  গ

  Concentration in the boundary

  ঘ

  It is an independent property
• A recrystallization texture is sometimes an advantage.
  ক

  True

  খ

  False
• What is most likely to happen to the grain boundary energy of a pure metal on alloying?
  ক

  It increases

  খ

  It reduces

  গ

  It increases first and finally becomes constant

  ঘ

  No effect
• Which among the following is the property of a low angle boundary?
  ক

  Areas of poor fit

  খ

  Relatively open structure

  গ

  Highly disordered

  ঘ

  Areas of perfect fit
• When α > 10-15° the boundary is known as a_______ (“α” is the angular misorientation across the boundary)
  ক

  Random high-angle grain boundary

  খ

  Random low-angle grain boundary

  গ

  Super angle grain boundary

  ঘ

  Axial grain boundary
• If the tilt boundary is unsymmetrical, dislocations with different Burgers vectors are required to accommodate the misfit.
  ক

  True

  খ

  False
• For simple arrays, the spacing of dislocation is given by the formula________ (where b is the Burgers vector of the dislocations and α is the angular misorientation across the boundary)
  ক

  D = b/sinα

  খ

  D = b/cosα

  গ

  D = b*sinα

  ঘ

  D = b*cosα
• “α” is the angular misorientation across the boundary. At very small values of α, the dislocation spacing is very large and the grain boundary energy ꙋ is approximately proportional to the____
  ক

  Position of dislocation

  খ

  Density of dislocation

  গ

  Type of dislocation

  ঘ

  Volume of dislocation
• In the edge dislocations, the Burger vectors and dislocation line are _________
  ক

  Parallel to each other

  খ

  Perpendicular to each other

  গ

  Close to each other

  ঘ

  Far away from each other
• Calculate the magnitude of Burgers vector for the BCC lattice expressed as ½<148>, where 1, 4, 8 are their respective components of Burgers vector and the value of “a’’ is given as 1?
  ক

  6.5

  খ

  4

  গ

  5.5

  ঘ

  4.5
• Which of the following boundary is related to screw dislocation?
  ক

  Low angle twist boundary

  খ

  High angle tilt boundary

  গ

  High angle cross boundary

  ঘ

  Low angle tilt boundary
• Which among the following boundary is an array of parallel edge dislocations?
  ক

  Low angle twist boundary

  খ

  High angle tilt boundary

  গ

  High angle twist boundary

  ঘ

  Low angle tilt boundary
• Which of the following boundary occurs when the axis of rotation is parallel to the plane of boundary?
  ক

  Roll in boundary

  খ

  Twist boundary

  গ

  Tilt boundary

  ঘ

  Roll out boundary
• The lattices of any two grains can be made to coincide by ________
  ক

  Twisting across the plane

  খ

  Twirling about multiple axis

  গ

  Turning in the direction of grain boundary

  ঘ

  Rotating one of them through a suitable angle about a single axis