大型TC18钛合金棒材多火次锻造过程的织构演变模拟  

Simulation of Texture Evolution of Large TC18 Titanium Alloy Bar During Multi-pass Forging

作　　者：李志尚 熊智豪 杨平[1] 顾新福 颜孟奇 沙爱学 Li Zhishang;Xiong Zhihao;Yang Ping;Gu Xinfu;Yan Mengqi;Sha Aixue(School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China;AECC Beijing Institute of Aeronautical Materials,Beijing 100095,China)

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]中国航发北京航空材料研究院,北京100095

出　　处：《稀有金属材料与工程》2022年第7期2446-2453,共8页Rare Metal Materials and Engineering

基　　金：National Science and Technology Project of China (JPPT-135-GH-2-017)。

摘　　要：使用了一种多尺度耦合的方法来预测大型TC18钛合金棒材织构。首先采用宏观有限元方法,模拟了TC18钛合金棒材在接近实际工艺条件下的多火次锻造过程,并得出了在锻造过程中棒材芯部与边部的等效应变及剪切应力σ分布不均匀的特征。然后,通过宏观有限元模型与介观粘塑性自洽模型(VPSC)多尺度耦合的方法模拟得到了锻造过程中棒材芯部和边部织构的演变情况。结果表明,六方锻造方式使棒材芯部由{110}<112>织构过渡到{111}<110>织构,并由{110}<110>织构过渡到{111}<110>织构。整个锻造过程中即是{111}型织构与{110}型织构相互转变的过程。这种过渡织构在极图中呈现出类似于剪切织构的特点,经分析:这种织构并非是剪切织构,而是锻造过程中由六方锻造方式和{110}、{111}型2类织构间的相互转变共同作用下形成的。经过棒材的形变过程,边部形成了{100}和{111}型2种织构。通过对比发现,六方锻造方式不仅不易生成{100}型织构,而且有利于{100}型织构的减弱和消除。拉伸试验结果表明,六方锻造样品的力学性能均达到标准要求。A multi-scale coupling method was used to predict the texture of TC18 titanium alloy bar. Firstly, the macroscopic finite element method was used to simulate the multi-pass forging process of TC18 titanium alloy bar under the conditions close to the actual ones, and the characteristics of inhomogeneous distribution of effective strain and shear stress σXYat the center and edge of the alloy bar during forging were obtained. Then, the multi-scale coupling method of macroscopic finite element model and mesoscopic visco-plastic self-consistent(VPSC) model was used to simulate the texture evolution at the center and edge of alloy bar during forging. The results show that in the center of the alloy bar, the texture transformation from {110} <112> to {111} <110> and from{110} <110> to {111} <110> occurs. The forging process is composed of mutual transformation between {111} and {110} textures.The transition texture shows the similar characteristics of shear texture in the pole figure. After analysis, it is confirmed that the transition texture is formed by the interaction of hexagonal forging and mutual transformation between {110} and {111} textures,which is not the shear texture. The {100} and {111} textures formed at edge were derived from the deformation process. Through comparison, it is found that the hexagonal forging can hardly produce the unfavorable {100} texture, and it is conducive to the weakening and elimination of {100} texture. The tensile test results show that the mechanical properties of the hexagonal forging specimen can meet the standard requirements.

关 键 词：钛合金 多火次锻造 织构 模拟 

分 类 号：TG319[金属学及工艺—金属压力加工]