《工程材料学(双语)课件》由会员分享，可在线阅读，更多相关《工程材料学(双语)课件（80页珍藏版）》请在金锄头文库上搜索。
1、Bilingual Language Teaching,工程材料学 Engineering Materials,2012. 11,提 要,教学目的 教学内容及重点 教学方法 使用教材,教学目的,材料成分组织性能用途关系； 掌握常用金属材料的基本理论知识，具有对给定零件选择合适钢种和热处理工艺的初步能力； 通过双语教学培养学生准确理解本专业外文科技文献的能力，为后续专业知识的拓广奠定必要的基础。,教学内容及重点,课堂教学（34学时） Chapter 7： Nonferrous Alloys （7学时） Chapter 8： Plain-carbon and Low-alloy Steels （1
2、8学时） Chapter 9： High-Alloy Steels（9学时） 实验环节（6学时） 实验一： 有色金属的显微结构观察 实验二：测定热处理对高速钢的显微组织和硬度的作用 实验三：铸铁显微组织的观察,教学方法,双语教学（ Bilingual Language Teaching ） 定义： 双语和双语教学的界定是将学生的外语或第二语言，通过教学和环境，经过若干阶段的训练，使之能代替，或接近母语的表达水平。 中国 采用“保持型双语教学”形式，即 学生刚进入学校时使用母语，然后逐渐地使用第二语言进行部分学科的教学，其它学科仍使用母语教学。 培养目标：1）获取学科知识（重点掌握专业知识）；
3、2）培养和提高学生运用外语的能力（用英语学）。,使用教材,主要教材： Engineering Materials and Their Applications” Richard A. Flinn, Paul K. Trojan John Wiley 肋状物，起肋作用的东西 structure: n.结构,构造 mechanical: 机械学的; 力学的; 物理上的 processing: n. (数据)处理, 加工工艺(生产方法)设计, 工艺过程,7.1 Overview,specification: n.详述, 常 pl. 规格, 说明书, 规范，规格、标准 course: n. 过程, 经
4、过, 进程, 课程, 一道菜； v.追猎, 急行, 运行, 流动 laughing stock: 笑柄 engineering department: 工程系 engineering drawing 工程图样, 工程制图 handbooks of standards: 标准手册,Vocabulary,box: 框;寄存器;框符 degasify: vt. 脱去, 除气 modify: vt. 变更, 修改，缓和, 减轻; 调节; 限制，变质孕育, 改善处理 component : n. 元部,组件,成部分 designation: n. 指出, 指明; 任命, 选派; 称呼; 名称;【军】番号
5、; 标号记, 志; 目的, 目标,Vocabulary,non-ferrous metal: 有色非铁金属 wrought: adj. 古work 的过去式及过去分词 制造的; 形成的; 精炼的, 锻成的 n.锻件、轧材和冷拨产品的总称,精制 wrought iron: n.熟铁, 锻铁 cast: 铸件n；浇铸v cast iron : 铸铁 component design: 零件设计,Vocabulary,Category,Category,7.2 Aluminum Alloys,Outline: Characteristics of pure Aluminum Principal al
6、loying elements Classification of Al alloys Heat treatment of Al alloys Recent research and development of Al alloys,=2.7g/cm3 light weight alloy T=660； Atomic structure 3 valence electrons in the outermost electronic shellgood electrical and thermal conductivity Unit cell FCC excellent ductility an
7、d formability, Excellent corrosion resistance,Characteristics of Pure aluminum,Principal alloying elements,Cu Solid solution strengthening; precipitate hardening Ambient-temperature Strength; heat resistance principal alloying element in high-strength Al alloys and heat-resistant Al alloys Mg Solid
8、solution strengthening Strength, density, corrosion resistance Mn Electro chemical characteristics of MnAl6 in Al-Mn alloy is similar to that of Al corrosion resistance Corrosion-resistant Aluminum alloys; wMn2%,Si second-phase strengthening Al-Si cast alloys (wSi=10-13%) Si+MgMg2Si precipitate (wSi
9、=1.0-1.2%) Zn high solubilitysolid solution strengthening wZn=0.4-0.8%strength, corrosion resistance precipitate-forming element in multi-component alloys precipitation strengthening Li density， elastic modulus Al3Li ordering precipitate phaseprecipitation strengthening; wLi3.0% in Al-Li alloys,Prin
10、cipal alloying elements,Cast Al alloys Wrought Al alloys heat treatable Al alloys non-heat-treatable Al alloys,Classification of Al alloys,Abroad 1XXX Al 2XXX Al-Cu 3XXX Al-Mn 4XXX Al-Si 5XXX Al-Mg 6XXX Al-Mg-Si 7XXX Al-Zn,Codes of Al alloys,Annealing Recrystallization annealing（full annealing） reli
11、eve work hardengingductility Low temperature annealing relieve internal stressmodestly ductilitygenerally 180300 Homogenization annealing (diffusion annealing) relieve composition segregation and internal stress Solid solution heat treatment,Heat treatment of Al alloys,Aging treatment natural aging;
12、 artificial aging; eg. Al-Cu alloy Optimal aging temperature Ts=(0.5-0.6)Tm Tm : melting temperature of the alloy Retrogression and re-aging(RRA) 回归再时效 process：aged alloy200250（several seconds/minutes）rapid cooling to room temperaturequenching state characteristics：slightly strength， corrosion resis
13、tance reason: G.P zone or metastable phase dissolving,Heat treatment of Al alloys,如Al-Zn-Mg-Cu系的7075合金，用单极峰值时效(T6)可达到最高抗拉强度，但应力腐蚀抗力降低。 为改善应力腐蚀抗力采用分级时效，即用110时效，保温8h，再177时效，保温8h，结果提高了应力腐蚀抗力，但强度降低了10%-15%。 而采用回归再时效处理，可以保持7075合金T6状态的高强度，又具备了分级时效处理的优良应力腐蚀抗力。,回归再时效应用举例,Rapid solidification(快速凝固) Al-Li all
14、oys,Recent research and development of Al alloys,How to raise the yield and tensile strength of pure Al（single-phase）?,Cold working 1060 0 annealing(退火) H18 cold-worked Solid solution strengthening 3003 0/H18 5052 0/H38 (1)Solid solution strengthening + (2)cold-working hardening (1) Mechanism: Solut
15、e atom（固溶原子） raises the stress required for slip; Function: retain the ductility and formability of the base metal. (2) Mechanism: related to the dislocation motion(位错运动),Two-phase wrought Al alloys,2014 (Al-4.5% Cu, in mass) at 550C+at room temperature A candidate for Age hardening (coherent 共格的 pr
16、ecipitate) How to produce fine coherent precipitate? Process: solid solution treatment (heated to 500-550C,quench)+aging at 170C for 10hr.,Cast Al alloys,Generally two-phase alloys Exception: relatively pure Al cooling fins-high thermal conductivity Strengthening methods: (1) Heat-treatable casting alloy356.0 Age hardening( Note: solid solution can be omitted if the cooling rate of the casting is enough fast )T5 (2) The second phase
