Choose the right description of a screw dislocation

A linear crystalline defect associated with the lattice distortion created when normally parallel planes are joined together to form a helical ramp. The Burgers vector is parallel to the dislocation line.

Determine the behavior of the crystal lattice when the crystal deforms plastically under the effect of tensile stress.

72. Find schematic illustration which represents covalent bonding?

73. Find crystallographic direction [110] in the figure.

Find crystallographic plane (110) in the figure.

75. How does the equilibrium density of vacancies change with the increase in temperature?

The equilibrium number of vacancies Nv for a given quantity of material depends on and increases with temperature according to

Thus, the number of vacancies increases exponentially with temperature

76. Which group of crystal lattices possesses the most atomic packing factor (APF)?

For the FCC structure, the atomic packing factor is 0.74, which is the maximum packing possible for spheres all having the same diameter.

77. How the bonding energy of a material is related to its melting temperature?

Materials having large bonding energies typically also have high melting temperatures

For the small-angle boundary find the right relationship between angle of misorientation, q, Burges vector, b, and distance between dislocations, D.

79. Describe the change of solubility limit of Sn in Pb from 0°C to T_E and from T up to ~330°C

80. Which definition of recrystallization is correct?

1) The formation of a new, strain-free grain structure from that existing in cold-worked metal, usually accomplished by heating. (2) The change from one crystal structure to another, as occurs on heating or cooling through a critical temperature. (3) A process, usually physical, by which one crystal species is grown at the expense of another or at the expense of others of the same substance but smaller in size.

Дата добавления: 2015-10-30