Deformation behavior of Ti-5Al-2Sn-2Zr-4Mo-4Cr alloy with two initial microstructures during hot working  

热加工过程中2种原始组织的Ti-5Al-2Sn-2Zr-4Mo-4Cr合金变形行为（英文）

作　　者：罗皎[1] 李莲[1] 李淼泉[1] 

机构地区：[1]西北工业大学材料学院,西安710072

出　　处：《Transactions of Nonferrous Metals Society of China》2016年第2期414-422,共9页中国有色金属学报（英文版）

基　　金：Projects(51205318;51275416)supported by the National Natural Science Foundation of China;Project(2012KJ02002)supported by the Innovation Fund of Science and Technology in Northwestern Polytechnical University,China

摘　　要：The effects of initial microstructure on the flow stress, strain rate sensitivity （m）, strain hardening exponent （n）, apparent activation energy （Q） for deformation of Ti-5Al-2Sn-2Zr-4Mo-4Cr alloy were investigated using isothermal compression tests. Results show that the alloy with Widmanst-tten alpha plates shows a higher peak stress and flow softening. Additionally, the alloy with equiaxed primary alpha exhibits an early yield drop at or above 810 ℃ and at strain rates of 0.1-5.0 s^-1. In the strain range of 0.5-0.7,m of the alloy with equiaxed primary alpha is found to be larger at 0.01 s^-1 and lower deformation temperatures. This phenomenon could be reasonably explained based on the microstructure evolution. The strain has a significant effect onn of the alloy with Widmanst-tten alpha plates, which is attributed to platelet bending/kinking and dynamic globularization ofα phase. In the strain range of 0.15-0.55,Q of the alloy with Widmanst-tten alpha plates is larger.采用等温压缩试验研究不同原始组织对Ti-5Al-2Sn-2Zr-4Mo-4Cr合金流动应力、应变速率敏感性指数、应变硬化指数和表观变形激活能的影响。结果表明：原始组织为片层组织的Ti-5Al-2Sn-2Zr-4Mo-4Cr合金具有更高的峰值应力和流动软化效应,当变形温度高于或等于810℃、应变速率为0.1-5.0 s-1时,原始组织为等轴组织的Ti-5Al-2Sn-2Zr-4Mo-4Cr合金存在初始屈服现象。当应变为0.5-0.7、变形温度较低、应变速率为0.01 s^-1时,原始组织为等轴组织的Ti-5Al-2Sn-2Zr-4Mo-4Cr合金的应变速率敏感性指数值较大,这主要归因于其显微组织演变特征。隋着变形的进行,原始组织为片层组织的Ti-5Al-2Sn-2Zr-4Mo-4Cr合金发生了α片层弯曲和动态球化现象,这使得其应变硬化指数变化显著。当应变为0.15-0.55时,原始组织为片层组织的Ti-5Al-2Sn-2Zr-4Mo-4Cr合金的表观变形激活能更大。

关 键 词：titanium alloy isothermal compression flow stress microstructure evolution dynamic globularization 

分 类 号：TG146.23[一般工业技术—材料科学与工程]