激光熔覆FeCrNiCoMnBx高熵合金涂层的组织结构与性能

Microstructure and properties of FeCrNiCoMnBx high-entropy alloy coating prepared by laser cladding

摘要:

采用激光熔覆技术制备FeCrNiCoMnB_x高熵合金涂层,研究了硼含量对激光熔覆FeCrNiCoMnB_x高熵合金涂层的组织结构、硬度和摩擦磨损性能的影响,以及硼化物中层错形成机制。结果表明：涂层均由简单FCC相和硼化物两相组成。当硼含量x≤0.75时,生成的硼化物以 (Cr, Fe)₂B相为主；而当硼含量x=1时,生成大量的(Fe, Cr)₂B相。随着硼含量的增加,涂层中的硼化物含量增加,硬度增大,耐磨性能增强。硼化物(Fe, Cr)₂B相在(10)中存在大量堆垛层错。硼化物中的层错是(Fe, Cr)₂B相通过(10) 面的层错(滑移距离为1/4[11])方式而向(Cr, Fe)₂B相转变而产生。

Abstract:

An FeCrNiCoMnB_x high-entropy alloy coating was prepared by laser cladding on a low carbon steel substrate. The effect of boron addition on the microstructure, hardness, and wear resistance of FeCrNiCoMnB_x was studied. The formation mechanism of stacking faults (SFs) in boride was analyzed. Results showed that the coatings had a simple FCC structure with boride precipitation. Boride precipitation was mainly the (Cr, Fe)₂B phase when the boron content x was increased from 0.25 to 0.75. However, as the value of x reached 1.0, many (Fe, Cr)₂B phases were found in the boride. The volume fraction of borides increased with the increase in boron content. Hardness and wear resistance of the coating were also enhanced with the increase in boron content. (Fe, Cr)₂B borides had high-density SFs on the (10) planes. The generation of SFs in (Fe, Cr)₂B occurred probably because of the (Fe, Cr)₂B → (Cr, Fe)₂B phase transformation generated by a simple shear of (Fe, Cr)₂B (10) planes (with shear vectors at nearly 1/4 [111]).