課程名稱︰材料科學概論 課程性質︰系選修 課程教師︰呂宗昕 開課學院：工學院 開課系所︰化工系 考試日期（年月日）︰100/1/10 考試時限（分鐘）：120 是否需發放獎勵金：是 （如未明確表示，則不予發放） 試題 : 1. (a) Please describe the behavior of creep.(4 Points) (b) Please describe the major three steps of fatigue failure.(6 points) (c) Please draw figures to show the fracture behavior for highly ductile materials, moderately ductile materials, and brittle materials.(6 points) 2. A copper alloy gas a plane strain fracture toughness if 52 MPa, It is found fracture results at a stress of 430MPa when the maximum interal crack length us 3.2mm. Compute the stress in the same alloy when fracture will occur for a critical interal crack length of 4.5mm.(15 points) 3. Steady state creep rate data are listed as below for aluminum @ 1200 degree C creep rate: 10E-4 (1/s) at stress = 12MPa creep rate: 10E-6 (1/s) at stress = 4MPa Compute the steady state creep rate @ 800 degree C when stress =11MPa. The activation energy for creep is 320 kJ/mol. (15 points) 4. (a) What is the crystal structure name and indicate the position of each ion for BaTiO3. (6 points) (b) Please calculate the ideal density of BaTiO3. Atomic weights of Ba, Ti, O are 137.34, 47.90, and 15.9994, respectively. The lattice constant of BaTiO3 is 0.42 nm. (6 points) 5. A parallel plate capacitor has an area of 8 E-3 m^2 and a plate separation of 4 E-4 m. The applied voltage is 30V. The polarization of the inserted material is 3 E-6 C/m^2. Calculate the dielectric constand of the material, the capacitance of the capacitorm the stored charge on each plate, abd the dielectric displacement. 8.85 E-12 is given. (20 points) 6. (a) Please draw the band structures for conductors such as Cu and extrinsic p-type semiconductors. (8 points) (b) Please draw a phase diagram for Al2O3-Cr2O3. These two materials form complete solid solutions. m.p. of Al2O3 = 2045 and of Cr2O3 = 2275 degree C. (4 points) 7. Calculate the conductivity of the doped silicon @ 30 degree C when 3 E16 1/m^3 phosphorus is doped in silicon. The electrical condoctivity for pure silicon @ 30 degree C is 7.6 E-4 1/(ohm-m), amd the electrom and hole mobility are 0.18 and 0.064 m^2/v-s, and e= 1.6 E-19. (10%) ends -- 十年生死兩茫茫　不思量　自難忘　千里孤墳　無處話淒涼 縱使相逢應不識　塵滿面 鬢如霜 夜來幽夢忽還鄉　小軒窗　正梳妝　相顧無言　唯有淚千行 料得年年腸斷處 明月夜 短松岡 --

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