添加微量硼对TiAl合金持久性能的影响

Effect of minor boron addition on creep rupture property of TiAl alloy

研究了Ti47.5Al2Cr2Nb合金中添加微量硼对合金760℃,275MPa持久性能的影响。结果表明:在同样的热处理制度下,添加0.2%(摩尔分数)硼能显著提高合金的持久寿命;尤其对于全片组织,其持久寿命由150.0h提高到460.5h,这主要归因于,添加微量元素硼抑制了连续冷却转变过程中魏氏片层束和羽毛状片层束在片层晶粒内的形成,从而提高了全片层组织的热稳定性。

The effect of minor boron addition on creep rupture property of Ti-47.5Al-2Cr-2Nb alloy under 760℃, 275MPa condition was investigated. The addition of 0.2%B into the alloy can effectively improve the creep rupture property, especially for the fully lamellar microstructure, the creep rupture life is prolonged from 150 h to 460.5 h. The main reason is that minor boron addition suppresses the formation of Widmfstatten lamellar colonies and feathery lamellar colonies in lamellar grains during continuous cooling transformation, and then improves the thermal stability of the fully lamellar microstructure.