铝合金表面高熵合金搅拌摩擦加工改性及性能研究

Surface Modification and Property of Aluminum Alloy by Introduction of High Entropy Alloy via Friction Stir Processing

利用搅拌摩擦加工技术,通过水下快冷的方式制备了铝基AlCoCrFeNi高熵复合材料,实现了对铝合金的表面改性。采用SEM、EBSD等测试手段对铝表面复合材料的微观结构进行表征,利用显微硬度计和摩擦磨损设备对复合材料的显微硬度和摩擦磨损性能进行了分析,并探讨了磨损机制。结果表明:高熵合金颗粒均匀地分布在铝基体中,且颗粒与基体界面上没有明显的界面反应层;铝表面复合材料的显微硬度和耐磨性能随着高熵合金颗粒含量的增加而显著提高;当高熵合金颗粒体积分数为15%时,复合材料显微硬度为147 HV0.2,磨损率为85×10~(-5) mm~3/m,分别较基材提高69%和降低43%.对磨损表面分析结果表明,随着高熵合金颗粒含量的增加,复合材料的主要磨损机制由黏着磨损转变为复合材料的磨粒磨损。

Aluminum-based AlCoCrFeNi high-entropy alloy(HEA)composite was fabricated by rapid cooling under water after applying friction stir processing to modify the surface properties of aluminum.The microstructure was characterized by using SEM and EBSD.The microhardness and tribological properties of composite were analyzed on microhardness tester and friction and wear equipment,and wear mechanism was discussed.The results show that the HEA particles are uniformly distributed in the Al matrix with refined grains,the particle-matrix interface is clean with no obvious interface reaction layer.The microhardness and wear resistance of Al surface composite are significantly improved with the increase of HEA particulate contents.When the volume fraction of HEA particles is 15%,the microhardness and wear rate of composite is 147 HV0.2 and 85×10-5 mm 3/m,which are 69%higher and 43%lower than those of the base material,respectively.The worn surface analysis reveals that the wear mechanism is transformed from adhesive wear to abrasive wear in the composite with the increase of HEA particulate contents.