(c) Is the (111) plane a possible slip plane in a BCC metals? Explain why. (3%) (6%)

(a) Detcrmine the three-axis Miller index and four-axis Miller-Bravais index for the plane ABCD. (4%)

(b) Determine the three-axis Miller index and four-axis Miller-Bravais index for the direction. (4%)

(c) Determine the planar packing fraction for the CDE planc. (4%)

(a) Why the critical resolved shear stress in a BCC (body-centered cubic) metal is higher than that in a FCC (face-centered cubic) metal? (3%)

(b) A single crystal of a BCC metal is oricnted such that the [120] direction is parallel to an applied tensile stress. If' slip occurs on a (112) plane, and the critical resolved shear stress is 48 MPa, Compute the yield streneth of the single crystal.

(a) During the solidification of pure metal, what are the two energics involved in the transformation? (4%)

(b) Write the equation for the total free-energy change involved in the solidification of liquid to produce a strain-free solid nucleus with a radius of R by homogencous nucleation. (4%)

(c) Describe and explain the change of the two energies during solidification transformalion.(4%)

4. Consider the impurity diffusion of phosphorus into a silicon wafer. If phosphorus is diffused into a thick silicon waler with no previous phosphorus in it at a temperature of 1100℃. If the surface concentr tration of the phosphorus is 1 x atoms/cm3and its eoncentration at ce of 1.2 Jum below the surface is atoms/cm3, how long must be required for the impurity diffusion? The difiusion coeficient for phosphorus diffusing in silicon at 1 100*C is 3.0 x. (10%) 

(a) Estimate the engincering strain just before yield. (3%)

110年 - 110 國立臺北科技大學_碩士班招生考試_材料科學與工程研究所：材料科學與工程導論#108255