NiCoCrAlYTa涂层/镍基单晶高温合金界面再结晶

Recrystallization on Interface between NiCoCrAlYTa Coating and Nickel-Based Super-Alloy

采用低压等离子喷涂技术在镍基单晶高温合金上制备了NiCoCrAlYTa涂层,通过不同的真空热处理和预处理制度研究其对涂层/镍基单晶界面的影响。结果表明,1080℃真空热处理界面扩散带均产生胞状再结晶体,而1000℃和850℃无再结晶产生。预处理时喷砂压力大于0.2MPa,在1080℃,6h热处理后再进行850℃,24h时效处理界面扩散带均产生再结晶体,无喷砂时无再结晶产生。同时热处理后界面处出现元素的相互扩散及富Ta的Ni2Ta和Cr2Ta相,Ta在胞状晶内偏聚。

The NiCoCrAlYTa coating was prepared on Ni-based single crystal super-alloys by low pressure plasma spraying （LPPS）. The influences of heat treatment and pre-peening on the interface recrystallization of NiCoCrAlYTa coating and nickel-based super-alloy substrate were investigated by X-ray, SEM, BES and EPXMA. It was found that cellular recrystallization occurred at the diffusion area of samples adopting the vacuum heat treatment at the temperature of 1080℃, while no recrystallization appeared at the temperatures of 1000℃ and 850 ℃ Recrystallization was also observed in the sample subjected by pre-peening with more than 0.2 MPa, followed by 1080 ℃, 6 h heat treatment and 850 ℃, 24 h aging treatment, while no recrystallization was observed in the sample subjected by no pre-peening followed by above mentioned heat treatment. The results revealed that element Ta aggregated within cellular grains and that inter-diffusion took place and Ta-rich phases （Ni2Ta, Cr2Ta） were formed at the interface through heat treatment.