(南昌航空大学 航空制造工程学院，南昌 330063)
摘 要: 在变形温度920~1040 ℃、应变速率0.001~70.0 s-1条件下，采用Thermecmastor-Z热模拟试验机研究Ti-5.6Al-4.8Sn-2.0Zr-1.0Mo-0.35Si-0.85Nd合金在α+β两相区变形时的流动行为和塑性变形机制，得到优化的工艺参数范围。结果表明：该合金在α+β两相区变形时的流动应力对变形温度和应变速率均较敏感，变形温度较低时(920、950和980 ℃)，流动应力曲线呈流动软化特征，变形温度较高时(1010和1040 ℃)呈稳态流动特征。失稳变形工艺参数范围为(920~930 ℃、0.2~70 s-1)和(1000~1040 ℃、1~70 s-1)范围，该区域易产生局部流动和机械失稳。综合加工图及微观组织观察结果，优化出的Ti-5.6Al-4.8Sn-2.0Zr-1.0Mo-0.35Si-0.85Nd合金α+β两相区变形时的工艺参数范围为(1000~1030 ℃、0.001~0.1 s-1)及(920~935 ℃、0.001~0.003 s-1)，其塑性变形机制为超塑性成形。
关键字: Ti合金；变形行为；工艺参数优化；加工图
（School of Aeronautical Manufacturing Engineering, Nanchang Hangkong University, Nangchang 330063, China）
Abstract:The flow behavior and plastic deformation mechanism of Ti-5.6Al-4.8Sn-2.0Zr-1.0Mo-0.35Si-0.85Nd alloy were studied by the hot compression, which was carried out on a Thermecmastor-Z simulator in the temperature range of 920-1040 ℃ and strain rate range of 0.001-70.0 s-1, and the optimization process parameter range was obtained. The results show that the flow stress of this alloy is sensitive to temperature and strain rate in the α+β range. The flow stress curves exhibit a flow softening behavior when the temperature is lower than or equal to 980 ℃; while the flow stress curves exhibit a steady-state characteristic when the temperature is higher than or equal to 1010 ℃. The processing map exhibits two instability fields: 920-930 ℃ at 0.2-70 s-1 and 1000-1040 ℃ at 1-70 s-1. In these instability fields, the flow location or mechanical instability occurs. Combining processing map with microstructure observation, the optimum deformation process parameters in α+β range for Ti-5.6Al-4.8Sn-2.0Zr- 1.0Mo-0.35Si-0.85Nd alloy are (1000-1030 ℃, 0.001-0.1 s-1) and (920-935 ℃, 0.001-0.003 s-1), respectively, and the corresponding plastic deformation mechanism is superplasticity deformation.
Key words: Ti alloy; defomration behavior; process parameter optimization; processing map
