个人信息Personal Information
副教授
硕士生导师
性别:男
毕业院校:大连理工大学
学位:博士
所在单位:机械工程学院
学科:车辆工程
办公地点:汽车基础实验教学中心A305
联系方式:13591183897
电子邮箱:yingliang@dlut.edu.cn
Experimental and computational study of microstructural effect on ductile fracture of hot-forming materials
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论文类型:期刊论文
发表时间:2018-05-02
发表刊物:MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
收录刊物:SCIE、EI
卷号:724
页面范围:298-323
ISSN号:0921-5093
关键字:Polycrystalline material; Crystal plasticity; Constitutive behavior; Dislocation density; Microscale damage; Thermo-mechanical processes
摘要:Thermo-mechanical experiments at different elevated temperatures are carried out for tensile and shear-dominant specimens extracted from warming forming materials of 7075 aluminum alloy and 22MnB5 boron steel, respectively. A specimen-embedded furnace jointed by temp-control system to perform the high temperature shear experiments. Driven by microscale anisotropic plastic flow, damage is embedded in each slip system and damage evolution is controlled by the preferential dislocation slip. Combined with microscale damage and dislocation density based constitutive model, an advanced crystal plasticity method is proposed to perform predictions of mechanical behavior of face-center-cubic materials at various temperatures. Reasonable agreement is obtained between experimental and numerical results for different specimens, temperature conditions and materials. This approach simultaneously captures the strain hardening rate, damage softening, non-linear post-necking and fracture strain. Microstructural effects on ductile fracture are tracked and investigated including dislocation density and crystallographic orientation. The results show that local dislocation density rise is associated with damage initiation. Different fracture morphologies and necking paths are caused by distinct initial misorientation distributions in comparison with experimental observation of 7075 aluminum alloy. Local misorientations are investigated and critical misorientation ranges are computed for promoting void growth in zigzag and straight fracture morphologies. Schmid factor is computed as not necessary variable to trigger void growth.