高压凝固Ti-48Al合金片层组织失稳机理

Instability Mechanism of Lamellar Structures of Ti-48Al Alloy Solidified under High Pressure

采用高压凝固设备制备了Ti-48Al(原子分数,%)合金,并在真空封装后进行热处理试验,研究热处理工艺对高压凝固Ti-48Al合金的片层组织失稳机理。结果表明,在低于共析转变温度进行热处理时,常压凝固Ti-48Al合金组织中较难发现α_2相颗粒,而高压凝固片层组织界面处已开始析出α_2相颗粒。加热至1280℃进一步确定,相比于常压凝固,高压凝固Ti-48Al合金更易分解,且片层组织中γ相优先分解,长杆状的残余α_2相经历球化长大,这为进一步研究高压下组织与相转变提供了基础,丰富了高压凝固理论。

Instability mechanism of lamellar structures of Ti-48Al alloy solidified under high pressure was investigated.The results indicate that after 1100℃/12 h air cooling,α_2 phase particles can hardly be seen in normal pressure solidified Ti-48Al alloy;however,α_2phase has been found in high pressure solidified Ti-48Al alloy.Increasing the temperature to 1280℃,the high pressure solidified Ti-48Al alloy is easier to decompose than the normal pressure solidified samples.Besides,αphase in the lamellar structure decomposes firstly and the long-α_2 phase experiences spheroidization and growth.It provides the basis of further studying on the microstructures and phase transformation of high pressure solidified Ti-Al intermetallics and enriches the theory of high pressure solidification.