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1、东北大学毕业设计（论文） 摘 要 I 纯铝在步进式连续挤轧变形中的 变形及晶粒细化的研究单位名称：材料物理与化学研究所 专业名称：材料物理东北大学毕业设计（论文） 摘 要 II 东 北 大 学东北大学毕业设计（论文） 摘 要 III 摘要 细晶强化能够在提高材料强度的同时提高材料的塑性。在传统的细化晶粒方法中， 大塑性变形方法以其可制备大块、致密的材料的同时兼有工艺简单、成本低廉等诸多 优点而被广泛研究，但这些方法大多是由于一些缺陷而无法满足大规模的工业化生产。 本文改进了实现材料大变形的实验装置，在有限元模拟（FEM）指导的情况下，探索了 纯铝在步进式挤轧变形中的变形及晶粒细化规律。 本文首
2、先是通过有限元模拟，发现挤轧变形时样品的推进长度、推进速度等因素 对挤轧变形过程有很大的影响，模拟后得出最佳的实验条件，然后根据模拟结果改进 实验装置以及实验条件。最后本文所采用装置推进长度为20mm，推进速度为5mm/s时， 可以使纯铝试样顺利地发生挤轧变形,使得材料晶粒发生明显细化。模拟结果表明，在 推进压力一定的条件下，样品挤轧变形速率仅和样品与轧辊间的摩擦系数有关，与轧 辊的转速无关。挤轧变形及热处理实验结果表明，当挤轧道次为4道次，退火温度为 200，退火时间为10min时，所获得的晶粒尺寸细小均匀，晶粒细化效果最好。 东北大学毕业设计（论文） 摘 要 IV 关键词：大塑性变形；晶粒
3、细化；有限元分析；微观组织；纯铝。东北大学毕业设计（论文） Abstract VI Abstract Fine-grain strengthening can improve the plasticity and toughness of materials at the same time. In traditional method of fine grains, large plastic deformation methods are widely praised highly, for its preparation that can make large, compact mate
4、rial with simple process, low cost, and many other advantages. But most of these methods cannot be applied for large- scale industrial production because of some defects at last. This article improves the material experiment device of large plastic deformation, and explores deformation behavior and
5、grain refinement of the pure aluminum in step-by-step continuous extrusion-rolling process under the condition of the finite element method guidance.This article founds some factors of extrusion-rolling deformation such as the length of pushing sample, and the velocity of pushing that has a big impa
6、ct on extrusion-rolling process by finite element method. The best experimental conditions can be obtained after finite element method, This article improves the material experiment device and experiment condition according to the results of the finite element method. This article shows it can make
7、extrusion-rolling deformation of pure aluminum sample smoothly with the equipment with 20mm-long of pushing sample and 5mm/s advancing speed; meanwhile the internal grain of material has been refined. Simulation results show that extrusion-rolling deformation rate of samples is only related with the
8、 coefficient of friction between the samples and the roll, and has nothing to do with the speed of the rolling, in the given conditions of propelling pressure. The results of extrusion-rolling deformation and the heat treatment experimental shows that the fine and uniform grain can be obtained under
9、 the shear deformation for 4 times, the annealing temperature is 200 , the annealing time for 10 min, and the effect of grain refinement is best.东北大学毕业设计（论文） Abstract VII Key words: large plastic deformation; grain refinement; finite element method (FEM); microstructure; pure aluminum东北大学毕业设计（论文） 目
10、录 IX 目录 毕业设计（论文）任务.I 摘要.III Abstract .V 目录 .VII 第1章 绪论.1 1.1 引言.1 1.2 强烈塑性变形（SPD）简介.3 1.2.1 高压扭曲变形法（High Pressing and torsion，HPT）.3 1.2.2 多次锻造法（Multiple Foring，MF） .5 1.2.3 循环挤压-镦粗法（Cyclic Extrusion-Compression，CEC） .6 1.2.4 折皱-压直法（Repetitive Corrugation and Straightening, RCS）.7 1.2.5 叠轧法（Accumulative Roll-Bonding，ARB）.7 1.2.6 等径角挤压法（Equal Channel Angular Pressing,ECAP）.8 1.2.7 表面机械研磨法（Surface Mechanical Grinding Treatmen- t ,SMGT） .10 1.3本文的研究内容及意义.11 第2章 研究方案.13 2.1 实验材料.13东北大学毕业设计（论文） 目 录
