微米和纳米Cr_3C_2对Co40合金等离子堆焊层组织与性能的影响

Effects of Micron and Nano Cr_3C_2 on Microstructure and Properties of Co40 Alloy Plasma Surfacing Layer

采用等离子堆焊技术在低碳钢表面分别制备了Co40合金堆焊层以及分别添加30%(质量分数)微米和纳米Cr3C2的Co40合金(Cr3C2/Co)复合堆焊层,对比研究了添加微米和纳米Cr3C2对Co40合金堆焊层组织与磨损性能的影响。结果表明:Co40合金堆焊层的组织主要为发达柱状晶及其间的网状共晶;微米Cr3C2/Co复合堆焊层中的柱状晶明显被打断、碎化,生长方向性减弱,且其组织更加均匀和细小;纳米Cr3C2/Co复合堆焊层的结晶方式则由亚共晶转变为共晶,其组织主要由共晶组织组成,且进一步细化和均匀化;与Co40合金堆焊层相比,微米Cr3C2/Co复合堆焊层的硬度和耐磨性分别提高了37%和29%,而纳米Cr3C2/Co复合堆焊层的硬度和耐磨性则分别提高了50%和55%。

The Co40 alloy surfacing layer, Cr3C2/Co composite surfacing layers with 30wt. ~ micron and nano Cr3 C2 respectively on the surface of low-carbon steel were obtained by plasma surfacing. Effects of micron Cr3C2 and nancrCr3C2 on the microstructure and properties of the Co40 alloy surfacing layer were studied comparatively. Results show that the Co40 alloy surfacing layer was composed of developed columnar crystals and reticular eutectic structure between the dendrites. The dendrites of micron-Cr3 C2/Co composite surfacing layer were broken and fragmented, the growth directionality of the columnar crystals was obviously weaken and the microstructure was refined and homogenized. The crystallization way of nano-Cr3 C2/Co composite surfacing layer transformed into eutectic way from hypoeutectic way, the microstructure was mainly composed of eutectic structure, which was further refined and became more homogeneous. Compared with the Co40 alloy surfacing layer, the hardness and wear resistance of the micron-Cr3 C2/Co composite surfacing layer were increased by 37~ and 29~, while the hardness and wear resistance of the nano-Cr3 Cz/Co surfacing layer were increased by 50% and 55%.