粉末冶金TA15钛合金高温塑性变形加工图

Processing Map of Powder Metallurgy TA15 Titanium Alloy for High Temperature Plastic Deformation

采用Gleeble-1500热模拟机对粉末冶金TA15钛合金进行热压缩试验。基于动态材料模型建立了粉末冶金TA15钛合金在温度850～1050℃,应变速率0.001～10 s-1范围内的加工图,并结合合金变形后的微观组织对加工图进行了解释。结果表明:在T=1000℃/=0.001～0.01 s-1的区域内,功率耗散效率η值大于60%,合金可能发生了大晶超塑性变形。在T=850℃/=0.001～0.01 s-1、T=900℃/=1～10 s-1、T=950℃/=0.01～1 s-1和T=1050℃/=1～10 s-1区域内η值小于30%,其变形后的试样出现纵向开裂或有粗大的β晶粒。在T=900～950℃/=0.001～0.01 s-1、T=950～1000℃/=1～10 s-1和T=1000～1050℃/=0.01～0.1 s-1区域内为动态再结晶区,η值为30%～60%,出现动态再结晶或回复现象。

Hot compressing tests on powder metallurgy （P/M） TA15 titanium alloy have been conducted by a Gleeble-1500 simulator. A processing map for P/M TA15 titanium alloy in the temperature range of 850-1050 ℃ and the strain rate range of 0.001-10 s^-1 was developed on the basis of a dynamic materials model and interpreted by microstructure observation. The results show that the alloy possesses superplasticity at the peak of power dissipation efficiency when deformed at T=1000 ℃/d =0.001 -0.01 s-1. The alloy exhibits instability regime at T=850 ℃/ε =0.001-0.01 sl, T=900 ℃/ε =1-10 sl, T=950 ℃/ε =0.01-1 s^-1 and T=1050 ℃/ε =1-10 s^-1 with the power dissipation efficiency lower than 30%. Surface cracks and coarse fl grains are observed. The deformation characteristics of P/M TA15 alloy at T=900 -950 ℃/ε =0.001-0.01 s-1, T=950 -1000 ℃/ε =1-10 s^-1 and T=1000-1050 ℃/g =0.01-0.1 s^-1, are recrystallization with the power dissipation efficiency of 30%-60%. Dynamic recrystallization or dynamic recovery can be observed in these domains.