• 对流换热过程的数学描述 • 强制流动时的对流换热 • 自然对流时的对流换热

西安建筑科技大学：《材料工程基础》课程教学资源（实验指导）实验讲义

第一节钢材的分类 1.按化学成分分类 (1)碳素钢。碳素钢的化学成分主 要是铁,其次是碳,故也称铁一碳合 金。其含碳量为0.02%~2.06%。此 外尚含有极少量的硅、锰和微量的硫 、磷等元素。碳素钢按含碳量又可分 为: 低碳钢(含碳量小于0.25%)、 中碳钢(含碳量为0.25%~0.60%) 高碳钢(含碳量大于0.60%)

3. 1 Basic concepts of al loys 1. Definition An alloy is the combination of metal(s) with other elements through chemical bonding. Termino logy

1. Deformation process of polycrystalline materials Deformation process of industrial material consists of three stages Elastic. which is reversible

Edge dislocation 1. Slip (glide) Dislocation motion vs. atom movement. Direction:l⊥讠 Plane:lb(l× Dislocation motion vs. crystal movement. → crystal movement→(dislocation motion)

6. 8 Diffusion Mechani sm Flick's' law in microscopic form 1. One dimensional diffusion. jump frequency period probability of atom jumping to nearest position

Discrepancies between theory and practice in Deformation. 1. Morphology of the surface in deformation. 2. The great difference between theoretical and actual strength of single crystals (. >>)

By cottrell atmosphere model, we can explain the sharp yielding phenomenon

2005 年度“国家精品课程”申报表