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1、硕士学位论文纯钛塑性变形行为的晶体塑性有限元模拟THE FINITE ELEMENT SIMULATION ON PLASTIC BEHAVIOR OF PURE TITANIUM黄晓华2010年7月学校代码： 10213密级：公开国内图书分类号： TG113.12国际图书分类号: 669.017.3工学硕士学位论文纯钛塑性变形行为的晶体塑性有限元模拟硕士 研究生：导师：申请学位：学科、专业：所在单位：答-1丄辩日期：授予学位单位：黄晓华来忠红 副教授 工学硕士 材 料 学 材料科学与工程学院 2010 年 7 月 哈尔滨工业大学Supervisor ：Academic Degree Appl
2、ied forSpeciality ：Affiliation ：Date of Defence:Degree-Conferring-Institution:Associate Prof. Lai ZhonghongMaster of EngineeringMaterials ScienceSchool of Materials Science andEngineeringJuly, 2010Harbin Institute of TechnologyClassified Index: TG113.12U.D.C: 669.017.3Dissertation for the Master Deg
3、ree in EngineeringTHE FINITE ELEMENT SIMULATIONON PLASTIC BEHAVIOR OF PURETITANIUMCandidateHuang Xiaohua哈尔滨工业大学工学硕士学位论文摘要本文采用晶体塑性有限元(Crystal Plasty Finite Element Method, CP-FEM)为基础，结合 Voronoi图表技术建立了包含纯钛材料基本参数的单晶 体和多晶体塑性变形有限元模型，从细观角度研究了晶体的变形行为。首先利用晶体塑性有限元方法，建立了纯钛单晶塑性变形模型，对钛单 晶体的拉伸变形行为进行了研究，模拟结果表明在边界
4、约束条件下，单晶体 拉伸变形的同时发生了取向的旋转，其滑移系的滑移方向会逐步趋向于与拉 伸方向平行。禾I用建立的单晶体模型研究了晶体初始取向与晶体滑移的宏观力学响关 系，结果表明，软位向方向拉伸的拉伸应力小于硬位向方向拉升应力，模拟 变形过程符合Schmid定律。通过Voronoi图表信息建立了 TA2多晶体模型，并模拟了拉伸变形，对 照真实材料拉伸实验，分析了晶体变形过程的外形、组织形貌及应力应变关 系，模拟与实验结果接近。分段表征了TA2多晶体模型变形的应力应变演化过程，描述了多晶体塑性变形弹性阶段、屈服阶段、硬化阶段与颈缩阶段 应力应变分布，详细分析了晶粒变形的不均匀性的微观机制，说明了
5、桔皮组 织的形成过程。分析了不同晶粒尺寸对多晶体塑性变形行为的影响，研究结果表明，随 着晶粒度减小，晶体屈服强度增大，硬化曲线变陡，结果符合Hall-Petch关系，预测 TA2 纯钛的 Hall-Petch 常数为 阮=64.9MPa，K=473.3MPaxpm2。利用设定同取向晶粒建立织构模型的方法研究了初始织构对多晶体变形 各向异性及应力应变关系的影响，结果表明随着织构强度的升高，多晶体变 形不均匀性增大，多晶体屈服强度升高，硬化曲线变陡。关键词：TA2纯钛；塑性变形；有限元模拟；晶粒取向；晶粒尺寸；织构#-哈尔滨工业大学工学硕士学位论文AbstractBased on Crystal
6、Plasty Finite Eleme nt Method (CP-FEM) and Voro noi diagram, the poly-crystal plasticity finite element model of single crystalline and polycrystalline materials of TA2 pure titanium is set up. And the deformation behavior of crystal from the microscopic view was researched by this fin ite eleme nt
7、model.The ten sile deformati on behavior of sin gle crystalli ne was studied firstly and the results show that the rotation of orientation occurred at the same time with the ten sile deformati on of sin gle crystalli ne and the slip directi on of slipsystems could gradually parallelled with the ten
8、sile directi on.s law.In flue nce of orie ntatio n factors duri ng un iaxial tension of si ngle crystal metal is studied using the model of single crystalline. The results show that differe nt orie ntati on factors have con tributed to the yield stre ngth and ten sile stress duri ng plastic deformat
9、i on. With the orie ntati on factor reduced, the yield sress of si ngle crystalli ne becomes lower, which accords with SchmidCompare the results of the model of sin gle crystalli ne with the results of the actual material tensile tests, the change of metallographic structure and the tensile curve fr
10、om simulation analysis results are well in agreement with that of experme nt. The relati on ship betwee n the deformati on course、the morphology of microstructures and the stress was an alyzed, the evoluti on of stress and strain of polycrystalli ne deformati on were catalyzed, the stress and strain
11、 distributio ns in elastic stage plastic stage hardening stage and the necking stage were described. The in homoge neity of micro mecha nism of plastic deformati on of polycrystalli ne was described in detail. Accord ing to the in homoge neity micro mecha ni sm, the formati on mecha nism of tan geri
12、 ne peel is in vestigated.The in flue nces of the differe nt grain size to the behavior of the plastic deformati on of polycrystalli ne were an alyzed. The yield stress in creased with the decreas ing of the size of crystal grains, the harde ning curve bega n to climb quite steeply and the maximum t
13、en sile stress in creased. The in creas ing rule accord with Hall-Petch s law, the predictive factors of TA2 titanium by simulation are1/2(y0 =64.9MPa, K=473.3MPaxm-IL哈尔滨工业大学工学硕士学位论文The in flue nces of the in itial texture to the ani sotropy of the polycrystalli ne deformati on were researched using
14、 the method of sett ing the texture model of same orientation grains. The results show that with the increasing of the strength of texture, the in homoge neity of the deformati on of polycrystalli ne in creased, the yield stress also in creases, the harde ning curve bega n to climb quite steeply and
15、 the maximum ten sile stress in creased.Keywords: TA2 pure titanium, plastic deoformation, plasticity finite eleme nt, crystal orie ntati on,size of crystal grains, texture#-哈尔滨工业大学工学硕士学位论文目录摘要IAbstractII第1章绪论11.1纯钛概述11.1.1纯钛的基本性质及用途 11.1.2纯钛塑性变形特征 31.2晶体塑性有限元方法 41.2.1有限元基本思想 41.2.2晶体塑性有限元方法研究的层次性 51.2.3晶体塑性有限元方法应用研究进展 71.3本文主要研究目的及主要研究内容 11第2章 研究材料及模型建立 122.1引言122.2 TA2纯钛材料基本信息 122.2.1 TA2纯钛单晶体材料信息 122.2.2 TA2纯钛多晶体材料信息 132.3晶体塑性理论方程与数值解法 162.3.1金属滑移几何和运动学 162.3.2率相关单晶体塑性本构理论 182.3.3多晶体塑性本构理论 212.3.4晶体塑性模型的数值实现与求解
