摘要本文在常规等径角挤压技术的基础上提出了一种侧挤结合正挤压新技术，并以纯铜为对象，采用Deform软件对侧挤结合正挤压进行了数值模拟，探讨了侧向挤压通道转角内、外圆角半径、摩擦因子、侧向通道转角、正挤压通道锥角、正挤压工作带以及温度等对等效应变大小与分布、挤压载荷等因素的影响。研究表明，随着侧挤压通道内圆角半径的增大，等效应变随之增大，所需载荷减小；随着外侧圆角半径增大，等效应变大小以及载荷都减小；随摩擦因子增大，等效应变与挤压载荷都增加；随着侧挤压通道转角的增加，等效应变与载荷都减小；随着材料初始温度的升高，等效应变大小增大，载荷减小；而正挤压锥角以及工作带长度对应变大小影响较小，工作带长度对载荷影响也较小，而锥角增大时载荷增大，通道长度过短时挤压有较为严重的弯曲，因此在设计凹模是可以考虑适当减小锥角和增加通道长度。综上所述，设计侧挤结合正挤压模具时，可以根据模拟所得的结果来设计凸、凹模等模具等的相关工艺参数，这样可以减小设计周期，缩减成本，有利于这项技术实现工业化大规模推广和使用。83521

毕业论文关键词：侧挤结合正挤；数值模拟；等效应变；挤压载荷

Abstract The paper proposes a kind of new technology of lateral extrusion combined with forward extrusion, uses Deform software to make numerical simulation of lateral extrusion combined with forward extrusion with pure copper as the object and discusses the influence of inner and outer round radius of lateral extrusion passage, friction factor, lateral passage corner, forward extrusion passage taper angle, forward extrusion work tape and temperature, etc。 on equivalent strain size and distribution and extrusion load。 The investigation indicates that with the increasing of lateral round radius, the equivalent strain size and load decrease; with the increasing of friction factor, the equivalent strain and extrusion load increase; with the increasing of lateral extrusion passage corner, the equivalent strain and load decrease; with the initial temperature rise of material, the equivalent strain increases and load decreases; while extrusion taper angle and working tape length has less effect on strain size and work tape also has less effect on load, while if the taper angle increases, load increases and the extrusion for too short passage will cause serious bending。 Thus, it can consider reducing taper angle and increase the length of passage when designing die。 To sum up, when designing lateral extrusion combined with forward extrusion die, we can design the related technological parameter of protruding die and die according to the result from simulation so as to reduce design period and cost as well as making the specimen accumulate high dependent variable through lateral extrusion combined forward extrusion and getting relatively even strain, which is good for the technology realizing industrial promotion and application in a large scale。

Keywords: lateral extrusion combined with forward extrusion; numerical simulation; effective strain; extrusion load

目录

第一章 绪论 1

1。1 引言 1

1。2 超细晶材料 1

1。3 超细晶材料制备方法 2

1。4 等径角挤压 4

1。4。1 ECAP变形晶粒细化机理 4

1。4。2 ECAP存在的问题 4

1。4。3 ECAP的应用前景 5

1。5 有限元模拟