晶核形成的原因:由分析知液态与固态的结构,配位数, 原子间距相似;进一步分析知,液态从长程而言,原子排列 是不规则的,但在近程有可能出现瞬间排列的规则性

内容简介: 本章讲述冲压模具设计与制造的基础知识。 涉及冲压和冲模概念、冲压工序和冲模分类;常见冲压 设备及工作原理、选用原则;冲压成形基本原理和规律;冲 压成形性能及常见冲压材料;模具材料种类、性能、选用原 则及热处理方法;模具制造特点、模具零件加工方法及应用 等

氢气氛下区熔拉制的鼓棱无位错硅单晶,原生晶体经化学腐蚀,观察不到缺陷,包括微缺陷。但当块状热处理后,经腐蚀常常观察到尺度mm数量级的氢致缺陷(φ型缺陷、麻坑)和微缺陷氢沉淀。为了消除这些缺陷,原生单晶需片状供应,片厚应小于1mm,或中照后的区熔(氢)硅单晶,片状,940℃、0.5h退火,均能消除之。在电力电子器件的应用中,管芯等级合格率可保持在80%以上

点缺陷的特点是在空间三维方向上的尺寸都很小，约为几个原子间距，又称零维缺陷 ⑴空位 ⑵间隙原子 ⑶置换 原子

9.1 Reverse Eutectoid Transformations 9.1.1 Intro to austenite in Fe-C system 9.1.2 Formation mechanism of austenite 9.1.3 Kinetics of austenitization 9.1.4 Austenite grain growth and its control 9.2 Eutectoid Transformations

8.1 Classification of Phase Transformations in Solids 8.2 Features of Phase Transformations in Solids 8.3 Thermodynamics for Phase Transformation in Solids 8.4 Kinetics for Phase Transformation in Solids

10.1 Martensite Transformations 10.1.1 Characteristics 10.1.2 Thermodynamics 10.1.3 Crystallographic Theory 10.1.4 Kinetics 10.2 Martensite Transformations in Steels 10.2.1 Crystal structure of martensite in steels 10.2.2 Microstructure of martensite in steels 10.2.3 Stabilization of austenite 10.2.4 Mechanical properties 10.3 Bainite Transformations 10.3.1 Characteristics and Microstructures 10.3.2 Transformation Mechanism 10.3.3 Kinetics and influencing factors 10.3.4 Mechanical properties

9.1 Reverse Eutectoid Transformations 9.1.1 Intro to austenite in Fe-C system 9.1.2 Formation mechanism of austenite 9.1.3 Kinetics of austenitization 9.1.4 Austenite grain growth and its control 9.2 Eutectoid Transformations 9.2.1 Intro to Pearlite in Fe-C system 9.2.2 Formation mechanism of pearlite 9.2.3 Kinetics of pearlite formation 9.2.4 Mechanical properties

9.1 Reverse Eutectoid Transformations 9.1.1 Intro to austenite in Fe-C system 9.1.2 Formation mechanism of austenite 9.1.3 Kinetics of austenitization 9.1.4 Austenite grain growth and its control 9.2 Eutectoid Transformations

8.1 Classification of Phase Transformations in Solids 8.2 Features of Phase Transformations in Solids 8.3 Thermodynamics for Phase Transformation in Solids 8.4 Kinetics for Phase Transformation in Solids