课程名称︰材料科学 课程性质︰必修 课程教师︰林辉政 开课学院：工学院 开课系所︰工科海洋 考试日期（年月日）︰99/11/08 考试时限（分钟）：100 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : 1.Calculate the force pf attraction between a Ca^(2+) and an O^(2-) ionic the center of witch are separated by adistance of 1.25 nm (6 pionts) 2.Some hypothetical mental has the simple cubic crystal structure shown in figure 1. If the its atomic weight is 74.5g/mol and the atomicradius is 0.145 nm, compute its density.(6 pionts) 3.Derive planar density expressions for FCC(100)and(110)planes in terms of the atomic radius R.(6 points) 4.Determine the Miller indices for the plane shown in the accompanying sketch in Figure 2.(8 points) 5.What is the composition, in atom persent, of an alloy that contain 33g copper and 47g zinc?(8 points) 6.Determine the approximate density of a Ti-6AI-4V titanium that has a composition of 90 wt% Ti,6 wt% Al, and 4 wt% V.(8 points) 7.Determine the ASTM grain size number if 25 grains per square inch are measured at a magnification of 75.(8 points) 8.Determine the carburizing time necessary to achieve a carbon concentration of 0.30 wt% at a position 4 mm into an iron-carbon ally that initially contains 0.10 wt% C, and the treatment is to be conducted at 1100 *C. Use the data in Table 1 and Table 2.(10 points) 9.Carbon is allowed to diffuse though a steel plate 10 mm thick. The concentrations of carbon at the two face are 0.85 and 0.40 kg-C/cm^3 Fe. which are maintained constsnt. if the preexponential and activation enery are 6.2*10^-7 m^2/s and 80,000 j/mol,respective, compute the temperatureat which the diffusion flux is 6.3*10^-10 kg/m^2-s.(8 points) 10.A cylindrical bar specimen of some mental alloy 10 mm in diameter is stressed elatically in tension. A force of 15000 N produces a reduction in specimen diameter of 7*10^-3 mm. Compute Poisson's ratio for this material if its elatic modulus is 100 GPa.(8 points) 11.A cylindrical mental specimen having an original diameter of 12.8 mm and gauge length of 50.80 mm is pulled in tension until facture occur.The diameter at the point of fracture is 8.13 mm,and the fracture gauge length is 74.17 mm. Calculate the ductility in terms of persent reduction in area and percent reduction in area and percent elongation.(10 points) 12.Caculate the atomic paking for HCP(see Figure 3).(10 points) --

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