TC18钛合金的超塑性行为与变形机制  

Superplastic Behavior and Deformation Mechanism of TC18 Titanium Alloy

作　　者：刁仲驰 姚泽坤[1,2] 申景园 刘瑞[1,2] 郭鸿镇[1,2] DIAO Zhong-chi YAO Ze-kun SHEN Jing-yuan LIU Rui GUO Hong-zhen(School of Materials Science and Engineering, Northwestern Polytechnical University, Xi＇an 710072, China ERC of Forging Technique for Less Deformable Materials, Xi＇an 710072, China)

机构地区：[1]西北工业大学材料学院,西安710072 [2]难变形材料锻造技术研究应用中心,西安710072

出　　处：《材料工程》2017年第5期80-85,共6页Journal of Materials Engineering

摘　　要：通过高温拉伸实验研究TC18钛合金在温度为720~950℃,初始应变速率为6.7×10^(-5)~3.3×10^(-1)s^(-1)时的超塑性拉伸行为和变形机制。结果表明:TC18钛合金在最佳超塑性变形条件下(890℃,3.3×10^(-4)s^(-1)),最大伸长率为470%,峰值应力为17.93MPa,晶粒大小均匀。在相变点Tβ(872℃)以下拉伸,伸长率先升高后下降,在温度为830℃,初始应变速率为3.3×10^(-4)s^(-1)时取得极大值373%,峰值应力为31.45MPa。TC18钛合金在两相区的超塑性变形机制为晶粒转动与晶界滑移,变形协调机制为晶内位错滑移与攀移;在单相区的超塑性变形机制为晶内位错运动,变形协调机制为动态回复和动态再结晶。Superplastic tensile behavior and deformation mechanism of TC18 titanium alloy were investigated by high temperature tensile test at 720-950℃ with initial strain rates of 6.7×10-5s-1-3.3×10-1s-1.The results show that under the optimal superplastic deformation condition （890℃ and 3.3×10-4s-1）,the maximum elongation is 470%, the peak stress is 17.93MPa and with uniform grain size.Below the phase transus Tβ,the elongation firstly increases and then decreases.A maximum elongation of 373% is obtained at 830℃ and with initial strain rate of 3.3×10-4s-1 and the peak stress is 31.45MPa.The superplastic deformation mechanism of the TC18 titanium alloy in two-phase region is mainly grain rotation and boundary sliding,and the deformation coordination mechanism is dislocation slipping and climbing; the superplastic deformation mechanism in single phase region is intragranular dislocation motion and the deformation coordination mechanism is dynamic recovery and dynamic recrystallization.

关 键 词：TC18钛合金  超塑性  显微组织  变形机制 

分 类 号：TG146.23[一般工业技术—材料科学与工程]