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以3次真空自耗熔炼的Ti-46Al-6(Cr,Nb,Si,B)(at%)(以下简称G4合金)合金为对象,采用恒温等应变速率热模拟压缩试验研究G4合金在1050～1250℃及0.001～1s-1应变速率下的高温流变行为和组织演变。结果表明,在高温变形过程中,G4合金呈现先硬化后软化的流变行为特征,组织由粗大的铸态γ+γ/α2近片层组织演变为细小的近等轴γ+α2组织;造成G4合金流变软化和组织演变的主要原因是动态再结晶(DRX)。变形温度和应变速率是影响G4合金高温流变和组织演变的2个主要因素。铸态G4合金在高温下的变形机制以γ/α2层片晶团的扭折、弯曲、球化和DRX以及γ晶粒的拉长、破碎和DRX为主,孪生变形也起到了一定的辅助作用。其最佳高温塑性变形温度为1150℃,应变速率应不大于0.1s-1。
A series of experiments were conducted to investigate the effect of G4 alloy temperature on the wear resistance of G4 alloy at 1050 for three time vacuum consumable Ti-46Al-6 (Cr, Nb, Si, B) (at%) High temperature rheological behavior and microstructure evolution at ~ 1250 ℃ and 0.001 ~ 1s-1 strain rate. The results show that the G4 alloy shows the characteristics of softening and rheological behavior after hardening first, and the microstructure evolves from coarse as-cast γ + γ / α2 near-lamellar microstructure into small near-axis γ + α2 microstructure. The main reason for the rheological softening and microstructure evolution of G4 alloys is dynamic recrystallization (DRX). Deformation temperature and strain rate are the two main factors affecting the high temperature rheological and microstructure evolution of G4 alloy. The deformation mechanism of as-cast G4 alloy at high temperature is dominated by kinking, bending, spheroidization, DRX, and elongation of γ grains, crushing and DRX of the γ / α2 lamella, twinning also played a certain role effect. The best high temperature plastic deformation temperature of 1150 ℃, the strain rate should not exceed 0.1s-1.