材料学概论

1. 材料学概论 清华大学材料科学与工程系 本科生课程 于荣海 (2008)

2. 形状记忆合金 Shape Memory Alloys

3. Definition of a Shape Memory Alloy Shape Memory Alloys (SMAs) are a unique class of metal alloys that can recover apparent permanent strains when they are heated above a certain temperature.

4. NiTi 合金的晶体结构 相变

5. Different phases of an SMA

6. Temperature-induced phase transformation of an SMA without mechanical loading.

7. Shape Memory Effect of an SMA

8. Temperature-induced phase transformation with applied load

9. 冷却 加热 变形 变形

10. Growth and decay of a martensitic arrow in an austenitic matrix upon cooling and subsequent heating. CuAl14Ni4.2 (wt%) single crystal Martensitic arrow in austenitic matrix. CuAl14Ni4.2 (wt%) single crystal

14. 储氢材料 Hydrogen Storage Materials

16. LaNi5+3H2LaNi5H6 Mg2Ni+2H2Mg2NiH4

19. AB5 type alloys. • (LaPrCeNd)(CoMnAlNi)5X 储氢充电电池原理 正极: Ni(HO)2 + OH- NiOOH- +H2O +e 负极：M+H2O + e  MH + OH-

21. 太阳能电池材料 1. Si 材料 多晶Si 单晶Si 非晶Si 2. 其它太阳能电池用材料 CuInGaSe 材料 TiO2------柔性太阳能电池材料

22. FUNCTION OF THE SOLAR CELL ... CONVERTSLIGHTINTOELECTRIC CURRENT I Solar Cell Load

23. 1.0 mm 0.4 mm 2.0 mm 0.7 mm 4x1021 IR Visible UV 3x1021 /sec/eV 2 2x1021 1x1021 0 0.5 1 1.5 2 2.5 3 3.5 4 c-Ge nc-Ge c-Si mc-Si Photon Energy (eV) Solar Spectrum Photons/m

24. Energy Band Structures and Conductivity Metals Semiconductors and Insulators

25. Silicon Doping Si(4 valence electrons) e- P (5 valence electrons) Forn-typedoping Results in extra electrons h+ B (3 valence electrons) Forp-typedoping Results in extra holes

26. The PIN Structure Contains positive mobile charge carriers Fixed dopant ions - - - - P - layer Static Electric Field I - layer + + + + N - layer Contains negative mobile charge carriers

27. Electrical Conductivity = I V d /(tw)  = oe-Ea/kT = qN I A + V - W Electrode Electrode d Film Thickness (t) Si film Glass Substrate

28. Hubble Telescope

29. Antarctica

30. Indiana-Colorado: 1250 miles; 43 miles/h

31. 纳米材料和纳米技术

32. 材料纳米科学和技术

34. Nanofabrication • Nanofabrication methods can be divided into • two categories: • Top-down methods • Example: lithography • Bottom-up methods • Example: quantum dots and self-assemble

35. Photolithography UV etchant substrate photoresist mask Spin coating Mask and expose Develop Etching Final Product Can make complex 3-D shapes using gray-scale techniques Resist removal

37. Electron Beam Lithography and Nanofabrication Exposure Electron Beam High MM PMMA Low MM PMMA Indium Tin Oxide Glass Bilayer e-beam resist structure. A high molecular weight PMMA is spun on top of a slightly more sensitive bottom layer of low melecular weight PMMA. Development Metal deposition Liftoff The resist is developed in MIBK:IPA giving an undercut. The resist is removed in a liquid solvent leaving the pattern.

39. Nanoparticles by Chemical Synthesis Fe(CO)5 Pt(acac)2 • A schematic diagram of preparing FePt nanoparticles by chemical synthesis

40. Self-assembled FePt Arrays Evaporation Method

41. Transforming a Nanowire into a Nanospring

42. Zigzag Gold Chain

43. Boron Nitride Nanotube

44. Superconducting Quantum Dots

45. 纳米碳管 Carbon Nanotubes