双相钛合金Ti-6Al-4V拉伸行为的晶体塑性有限元研究  

Crystal plasticity finite element study of tensile behavior of two-phase titanium alloy Ti-6Al-4V

作　　者：张龙 常乐[1,2] 林鸿运[1,2] 周昌玉 Zhang Long;Chang Le;Lin Hongyun;Zhou Changyu(School of Mechanical and Power Engineering,Nanjing Tech University,Nanjing 211816,Jiangsu,China;Institute of Reliability Centered Manufacturing,Nanjing Tech University,Nanjing 211816,Jiangsu,China)

机构地区：[1]南京工业大学机械与动力工程学院,江苏南京211816 [2]南京工业大学高端装备可靠性制造研究院,江苏南京211816

出　　处：《钢铁钒钛》2024年第6期64-73,共10页Iron Steel Vanadium Titanium

基　　金：国家自然科学基金(51905260)。

摘　　要：通过晶体塑性有限元方法探究了α/β相含量和晶粒尺寸对Ti-6Al-4V双相钛合金拉伸力学性能的影响,通过滑移相对分数定量化评估不同滑移系对塑性变形的贡献。结果表明:Ti-6Al-4V钛合金拉伸变形过程中应力应变分布不均匀,应力集中在β相变体晶粒及晶界处,应变集中在α相晶粒附近。随β相含量升高,应力集中区域更多,三叉晶界处越易产生应变集中,β相{110}滑移系对塑性变形的贡献大幅提高。随着α相、β相或两相晶粒尺寸同时扩大,塑性段应力应变曲线下降,且初始变形都主要由柱面滑移系主导,锥面滑移系贡献次之。增大α相晶粒尺寸,锥面滑移系活性下降,导致塑性阶段应力值降低。增大β相晶粒尺寸,塑性阶段应力的降低与β相中{110}滑移系活性下降有关。同时增大α及β相晶粒尺寸时,会同时影响柱面滑移系和{110}滑移系的相对分数,应力值的下降与界面数量的显著下降有关。The influence of a/βvolume fraction and grain size on the tensile mechanical properties of Ti-6Al-4V dual-phase titanium alloy was investigated in this study using the crystal plasticity finite element method.The contribution of different slip systems to plastic deformation was evaluated quantitatively by slip relative fraction.The results demonstrate that the stress-strain distribution during the tensile deformation of Ti-6Al-4V titanium alloy is non-uniform.The stress is primarily concentrated on theβphase grain and grain boundary,while the strain is concentrated on theαphase grain.Increasing the volume fraction ofβphase leads to a larger stress concentration area,easier generation of strain concentration at the triple-junction of grain boundaries,and a significant increase in contribution from theβphase(110)slip system to the plasticity deformation.Increasing a,βor two-phase grain size results in decreased stress-strain curve in the plastic region,where initial deformation is predominantly governed by prismatic slip system while pyramidal<c+a>slip system contribute slightly less.An increase in aphase grain size leads to a decrease in the activity of pyramidal<c+a>slip system,resulting in reduced stress values in the plastic region.Increasing theβ-phase grain size results in a reduction of stress during the plastic stage,which is attributed to the decreased activity of(110)slip system within theβ-phase.Simultaneously increasing the grain size of both theαandβphases will affect the activation fraction of prismatic and(110)slip systems.The reduction in stress is associated with the significant decrease in the number of interfaces.

关 键 词：TI-6AL-4V 拉伸行为 晶体塑性 应力应变 滑移系 有限元分析 

分 类 号：TF823[冶金工程—有色金属冶金] TG115[金属学及工艺—物理冶金]