The service performance of the turbine blade root of an aero-engine depends on the microstructures in its superficial layer. This work investigated the surface deformation structures of turbine blade root of single crystal nickel-based superalloy produced under different creep feed grinding conditions. Gradient microstructures in the superficial layer were clarified and composed of a severely deformed layer (DFL) with nano-sized grains (48–67 nm) at the topmost surface, a DFL with submicron-sized grains (66–158 nm) and micron-sized laminated structures at the subsurface, and a dislocation accumulated layer extending to the bulk material. The formation of such gradient microstructures was found to be related to the graded variations in the plastic strain and strain rate induced in the creep feed grinding process, which were as high as 6.67 and 8.17 10⁷ s⁻¹, respectively. In the current study, the evolution of surface gradient microstructures was essentially a transition process from a coarse single crystal to nano-sized grains and, simultaneously, from one orientation of a single crystal to random orientations of polycrystals, during which the dislocation slips dominated the creep feed grinding induced microstructure deformation of single crystal nickel-based superalloy.

航空发动机涡轮叶片根部的使用性能取决于其表层的微观结构。本工作研究了不同蠕变进给磨削条件下生产的单晶镍基高温合金涡轮叶片根部的表面变形结构。表层中的梯度微观结构得到澄清，并由最上表面具有纳米级晶粒（48-67 nm）的严重变形层（DFL）、具有亚微米级晶粒（66-158 nm）和微米级的 DFL 组成。次表面大小的层状结构，以及延伸到块体材料的位错累积层。发现这种梯度微观结构的形成与蠕动进给磨削过程中引起的塑性应变和应变速率的梯度变化有关，这些变化高达 6.67 和 8。分别为⁷ s ^-1。在目前的研究中，表面梯度微观结构的演变本质上是一个从粗大的单晶到纳米尺寸的晶粒，同时从单晶的一个取向到多晶的随机取向的转变过程，在此期间位错滑移占主导地位。蠕变进给磨削诱导单晶镍基高温合金显微组织变形[J].