EB-PVD制备NiCoCrAl薄板800℃组织演变规律研究

Study on the Microstructure Evolution of NiCoCrAl Sheet Deposited by EB-PVD at 800℃

对电子束物理气相沉积（EB-PVD）制备Ni基高温合金超薄板800℃真空保温过程中的组织演变规律进行了研究。结果表明：制备态NiCoCrAl合金组织为Ni基固溶体，组织致密均匀，无位错，存在孪晶，但有大量应变条纹；在800℃、5×10^-3Pa真空保温过程中，合金组织仍为Ni基固溶体．合金平面和截面组织呈现层片状结构，无沉淀析出物，存在大量亚结构缺陷——挛晶、少量位错；随着合金保温时间的延长，应变条纹随之消除，沿（220）晶面的晶粒择优取向迅速长大。

The microstructure evolution of NiCoCrAl sheet fabricated by electron beam-physical vapor deposition （EBPVD） at 800℃ for different time （2 h,4 h,16 h,30 h） in 5×10^-3 Pa vacuum was studied. The results showed that the mierostrueture of original state was solid solution of nickel-based, the densified structure, without dislocations, including twinning crystals, but existed strain fringe; there weren＇t precipitates which were separated out in superalloy, still kept solid solution of nickel-based at 800℃, the mierostruetures of the surface and section take on layered fabric, and it included lots of substructures in the superalloy, such as twinning crystals, few dislocations. With the extension of heat preservation, the grains on （220） surface grew by preferential orientation rapidly, and stress was eliminated gradually.