不同固溶冷速GH4096高温合金在高温蠕变测试中γ'相的演变行为

Behavior of γ’precipitates under high temperature creep of GH4096 superalloy with different solution treatment cooling rates

采用5种常见的冷却方式对析出强化型GH4096高温合金进行固溶冷却,分别制备了5种冷速下的标准尺寸涡轮盘挡板件。试样在700℃、690 MPa下进行高温蠕变测试,比较了5种冷却工艺下GH4096高温合金的性能。通过引入一种新颖的原位统计表征手段,以图像的形式跨尺度地实现了对合金材料中的强化相——一次、二次、三次γ’相的原位观察和统计定量分布观察,并比较和探讨了高温蠕变前后材料中γ’相形貌和尺寸分布的变化。结果表明:5种冷速方式得到的GH4096高温合金均展现较好的高温蠕变性能。5种工艺下的材料中γ’相分布密度为210~260个/μm^(2),经过高温蠕变测试以后,γ’相数量显著减少,γ’相分布密度降为150~200个/μm^(2)。其中γ’相密度的降低,主要是由直径小于36 nm的γ’相减少所导致。

Precipitation-strengthened solution treated GH4096 superalloy was cooled by five different cooling methods.Standard size turbine disc baffles under five cooling rates were prepared separately.The specimens were subjected to high temperature creep tests at 700℃ and 690 MPa,and the performance of the five GH4096 superalloy disc baffles was compared.By introducing a novel in-situ statistical characterization method,the in-situ observation and statistical quantitative distribution observation of the strengthening phase in the alloy material-primary,secondary,and tertiaryγ’phases were realized across scales in the form of images.The changes of γ’phase morphology and size distribution in the materials before and after high temperature creep were compared and discussed.The results show that the GH4096 superalloys obtained by the five cooling rates all exhibit good high-temperature creep properties.The γ’phase distribution density of the materials under the five processes is 210-260μm^(-2).After the high temperature creep test,the number of γ’phases is significantly reduced,and the γ’phase distribution density drops to 150-200μm^(-2).Among them,the decrease of γ’phase density is mainly due to the decrease of γ’phases with a diameter less than 36 nm.