Heterogeneous random medium plasticity and fracture model of additively-manufactured Ti-6A1-4V
Heterogeneous random medium plasticity and fracture model of additively-manufactured Ti-6A1-4V
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DOI：
10.1016/j.actamat.2018.02.025
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发表时间：
2018-04-15
期刊：
影响因子：
9.4
通讯作者：
Mohr, Dirk
中科院分区：
文献类型：
--
作者：
Gorji, Maysam B.;Tancogne-Dejean, Thomas;Mohr, Dirk
通过成形金属沉积制成的Ti-6Al-4V结构的大变形响应严重地受到由制造工艺引起的先前β晶粒结构的影响。基于超过25个拉伸和剪切实验上的个人先验β晶粒，统计分布的各向同性硬化响应的先验β晶粒被确定。与晶体塑性有限元（CPFE）分析密切类似，Voronoi镶嵌用于生成包含多个先前β晶粒的增材制造结构的有限元模型。对于每个先验β晶粒，使用来自Hockett-Sherby型硬化曲线的截断高斯分布的随机拉力来分配不同的硬化曲线。同样，Hosford-Coulomb断裂起裂模型的参数进行了分配。CPFE模拟结果与拉伸试样的实验结果包含多个先前的β晶粒的比较，表现出良好的定性和定量协议方面的力-位移响应，表面应变场，和断裂发生。结果表明，增材制造的Ti-6Al-4V部件通过延性断裂失效需要非均匀随机介质建模方法。虽然本研究的重点是强度和硬化的变化，它是注意到，进一步的改进，预计当考虑到已知的纹理不匹配的先验β晶粒之间的沿着与详细的模型的先验β晶界。(c)2018 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
The large deformation response of Ti-6Al-4V structures made through shaped metal deposition is heavily affected by the prior-beta grain structure induced by the manufacturing process. Based on more than 25 tension and shear experiments on individual prior-beta grains, the statistical distribution of the isotropic hardening response of prior-beta grains is identified. In close analogy with Crystal Plasticity Finite Element (CPFE) analysis, Voronoi tesselation is used to generate finite element models of additivelymanufactured structures containing multiple prior-beta grains. For each prior-beta grain, a different hardening curve is assigned using a random pull from the truncated Gaussian distribution of Hockett-Sherby type of hardening curves. Similarly, the parameters of the Hosford-Coulomb fracture initiation model are assigned. The comparison of the CPFE simulation results with the experimental results on tension specimens containing multiple prior-beta grains, shows good qualitative and quantitative agreement with regards to the force-displacement response, the surface strain fields, and fracture occurrences. The results demonstrate that the failure of additively-manufactured Ti-6Al-4V components through ductile fracture requires a heterogeneous random medium modeling approach. While the present study focuses on strength and hardening variations, it is noted that further improvements are expected when considering the known texture mismatch between prior-beta grains along with detailed models of the prior-beta grain boundaries.(c) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.