4.9 Comparison Between Slip and Twinning Similar ity Both slip and twinning are shear process under shear stress T I. Differences 1. Orientation 2. Atom movement 3.y,△ a) Structure: Twinning is easy 4. Conditions b) Temperature da d c) Strain rate (c

2.7 Some Important Crystallographic Formulas 1. Zone and zone equation All Planes parellel to common axis [uvw] constitute a (crystal) zone, the [u v w] zone. If (h k l) belongs to zone [u v w], then hukv+=0 2.ifhuk+hw=0,then[uvw] lies in(hk) 3. For cubic crystals, [h (h k)

Paulings three rules governing the structure of ionic compounds 1. Anion Coordination polyhedron rule Each cation is surrounded by an anion polyhedron, the distance between anion and cation is r=rt tr, while the cn depends on rt/r

2.1 要点扫描 2.1.1 点缺陷及其平衡浓度 2.1.2 位错的基本类型及柏氏矢量 2.1.3 位错的应力场 2.1.4 位错的弹性能和线张力 2.1.5 作用在位错上的力和 Peach-Koehler 公式 2.1.6 位错间的交互作用 2.1.7 位错的起动力——Peirls-Nabarro 力 2.1.8 FCC 晶体中的位错 2.1.9 位错反应 2.1.10 HCP、BCC 及其他晶体中的位错 2.1.11 晶体中的界面与表面 2.1.12 位错的观察及位错理论的应用 2.2 难点释疑 2.2.1 柏氏矢量的守恒性 2.3 解题示范 2.4 习题训练

3. Application of Schmid's law How to determine the active S.S. for all the equivalent S.S. 2 Determine the active S.S. by Reflection Rule. Orientation cell for cubic crystals. Given: BCC Crystal having {110}slip system. Determine: active slip system in response to tensile loading along

Introduction 1. Definition: Fis a fictitious force which is supposed to be responsible for the motion of dislocation. Fll Criterion: The work done on crystal by stress must be equal to that done on dislocation by force F. 2. Principle of derivation of F: Macroscopic work=microscopic work (or deformation work)

1、材料设备的腐蚀与防护基本原理 2、设备腐蚀防护技术 3、材料的选用 4、保温目的 5、保温材料介绍 6、保温结构与施工

1. Sing le crystal ver sus po l crystal 1. For single crystals there is only one type of structure with same orientation Single crystals is characterized by anisotropy 2. Polycrystal consists of a lot of grain, small single crystals, With same structure but different orientations. These small single crystals are called grains. The boundaries between them are called grain boundaries

一、教学目标和教学内容 1．教学目标 通过本章学习，掌握应力状态的概念及其研究方法；会从具有受力 杆件中截取单元体并标明单元体上的应力情况；会计算平面应力状态下 斜截面上的应力；掌握平面应力状态和特殊空间应力状态下的主应力、 主方向的计算，并会排列主应力的顺序；掌握广义胡克定律；了解复杂 应力状态比能的概念；了解主应力迹线的概念

一、教学目标和教学内容 1．教学目标 让学生掌握杆件弹性应变能的有关概念。 理解和掌握在工程力学有广泛应用的能量方法。 掌握功能原理、功的互等定理、位移互等定理、卡氏定理。 能够熟练地计算基本变形杆件和常见的组合变形杆件的应变能