義守大學 96 學年度博士班入學招生考試試題 系所 科目 材料科學與工程學系 材料科學【不可使用計算機】 頁數 1/1 ※ 此為試題卷,考生請於答案卷上作答。 (每題 10 分) 1. Slip lines in bcc metals are often wavy and ill defined. Why? 2. Derive the Frank relation for simple tilt low angle boundary (with an array of edge dislocations). 3. It impossible for a homogeneous nucleation of dislocation under a normal applied stress? Explain the reason and find out the methods of substitution. 4. At grain boundaries, why the dislocation pile-ups can nucleate either yielding in the adjacent grains or boundary cracks? 5. Explain the reason for the work hardening in metals during plastic deformation? 6. What is the Burgers vector of a dislocation? How to determine it? 7. Describe for the mechanisms for stage I, II, III during working hardening in terms of dislocation dynamics. 8. Derive the rule of mixture for composite with continuous fibers under uniaxial tension along longitudinal direction. 9. Explain the phenomenon of ductile to brittle transition in alloy. 10. What is the dynamic strain aging effect in the alloys with high solute contents strengthened by solution hardening? 第1頁