不锈钢表面激光合金化Mn-Al_2O_3强化层的组织及性能

Microstructure and properties of laser alloyed Mn-Al_2O_3 layer on stainless steel

基于高速混合机桨叶所用奥氏体不锈钢的失效情况,利用激光合金化技术在奥氏体不锈钢上制备合金化强化耐磨层。利用光学显微镜、扫描电镜、X射线衍射仪、显微硬度计和光学分析仪研究合金化层的显微组织、成分、物相、横截面的硬度分布,同时利用正交试验得到激光合金化技术的优化参数。结果表明:当硬质相Al2O3的含量为70%,激光功率为2 kW,扫描速度为15 mm/s时,合金化层的显微硬度最大,达到440.8 HV0.1;所制备的合金化层无裂纹和气孔等缺陷,与基体形成冶金结合;合金化层由枝晶和枝晶间共晶组成,其相组成为奥氏体、Al2O3、Cr7C3、Mn7C3和Mn2O3;合金化层的耐磨损性能较基体的显著提高。

Based on the failure of austenitic stainless steel used in high-speed mixing blades, the laser alloying technique was used to fabricate the alloyed layer on stainless steel. The microstructure, composition, phases, microhardness of the cross-section of the alloyed layer were analyzed by OM, SEM, XRD, microhardness tester, optical profiling system, and the optimal parameter is obtained by the use of orthogonal. The results indicate that, the highest hardness is 440.8 HV0.1 when the content of Al2O3, the laser power and laser scanning speed are 70%, 2 kW and 15 mm/s, respectively. The alloyed layer is free of cracks with good processability, the alloyed layer is composed of dendrites and eutectic, the phases are austenite, Al2O3, Cr7C3, Mn7C3 and Mn2O3. The wear resistance of alloyed layer increases significantly.