Al含量对单晶高温合金1100℃长期时效后组织和持久性能的影响

Effect of Al Content on Microstructure and Stress Rupture Properties of Single Crystal Superalloys After Long-Term Aging at 1100℃

研究了两种不同Al含量单晶高温合金的热处理态组织和1100℃不同时间长期时效处理后的组织形貌以及长期时效对两种合金持久性能的影响,考察Al含量对合金组织稳定性以及持久性能的影响机理。研究结果表明:两种不同Al含量的合金经完全热处理后,5.7Al合金与6.1Al合金的γ′相尺寸相当,和5.7Al合金相比,6.1Al合金的γ基体通道略窄,体积分数从65%增加至70%左右;1100℃长期时效过程中,5.7Al合金的γ′相的长大速率低于6.1Al合金,TCP相的析出倾向明显小于6.1Al合金,5.7Al合金的组织稳定性高于6.1Al合金;经1100℃长期时效处理的两种不同Al含量合金试样在1120℃/137 MPa下的持久寿命均随长期时效时间延长而降低,长期时效1000 h后,两种合金的持久寿命均约为热处理态的50%;在不同长期时效时间下5.7Al合金的持久寿命都略高于6.1Al合金。

The two kinds of single crystal superalloys with different Al content,named as 5.7Al and 6.1Al,were prepared to study their microstructure after heat treatment,and the effect of long-term aging at 1100℃on the microstructure and stress rupture properties of the two alloys were studied.The influence mechanism of Al content on the microstructure stability and stress rupture properties of the alloys was also discussed.The results show that the size ofγ′phase in the 6.1Al alloy is nearly the same as that in the 5.7Al alloy after complete heat treatment,theγmatrix channel is slightly narrower,and the volume fraction ofγ′phase in the 6.1Al alloy increases from 65%to 70%.During the long term aging at 1100℃,the growth rate ofγ′phase in the 5.7Al alloy is lower than that in the 6.1Al alloy;the precipitation tendency of TCP phase is less than that of the 6.1Al alloy,so the microstructure stability of the 5.7Al alloy is higher than that of the 6.1Al alloy.With the prolongation of long-term aging time at 1100℃,the stress rupture life of two alloys with different Al content under 1120℃/137 MPa all decreases.After long term aging for 1000 h,the stress rupture life of both alloys is about 50%of that of the heat-treated samples.The stress rupture life of the 5.7Al alloy are slightly higher than that of the 6.1Al alloy.