Ti43Al5Nb0.03Y合金高温热压缩行为及其组织演变

Hot Compression and Microstructural Evolution of Ti43Al5Nb0.03Y Alloy

摘要:

在热模拟试验机上对Ti43Al5Nb0.03Y合金进行压缩变形实验，温度范围为1050~1200 ℃，应变速率范围为10-3~10-1 s-1，获得了其真应力-真应变曲线，并对热变形组织进行显微分析。结果表明：在低于1200 ℃的条件下，材料的锻后组织为残余层片和再结晶晶粒的混合组织，而温度达到1200 ℃时，材料锻后得到完全再结晶组织；在实验所涉及的温度及应变速率范围内，Ti43Al5Nb0.03Y合金的塑性变形机制主要为γ相中的滑移和孪生，其流变软化机制主要为γ相动态再结晶以及少量的γ相中的回复；该合

Abstract:

Thermo-mechanical processing parameters of Ti-43Al-5Nb-0.03Y (mole fraction, %) alloy are investigated by hot simulation tests at 1050~1250 ℃ on Gleeble-1500D with a nominal deformation of 50% and a strain rate of 10-1~10-3?s-1. The true strain–true stress curves have been obtained and the microstructures are observed. The results show that the microstructure consists of recrystallized grains and remained-lamellar when the compression temperature is lower than 1200 ℃, and of recrystallized grains at 1200 ℃. The major mechanism of plastic deformation is the slip deformation and twinning deformation, and the main softening mechanism is dynamic the recrystallization and dynamic recovery in the γ phase. The crack-free pancakes are obtained at a hot compressive temperature of 1200 ℃ and a strain rate of 10-3 s-1.