AZ91D镁合金表面激光熔凝温度场的数值模拟及其摩擦学性能  

Numerical Simulation of Temperature Field of Laser Surface Remelting on Magnesium Alloy and Evaluation of Friction and Wear Behavior of the Coating

作　　者：徐家乐[1] 李忠国[1] 郭华锋[2] 蒋希芝 王凯[1] 

机构地区：[1]江苏科技大学机械工程学院,江苏镇江212003 [2]徐州工程学院机电工程学院,江苏徐州221008 [3]江苏科技大学材料科学与工程学院,江苏镇江212003

出　　处：《材料保护》2014年第3期8-11,68,共4页Materials Protection

基　　金：江苏省高校自然科学研究项目(11KJD460004);江苏科技大学研究生科技创新计划(YCX13S09)资助

摘　　要：激光熔凝温度场的变化对熔凝层性能有重要影响。目前,将温度场数值模拟及熔凝层性能结合的研究报道较少。对AZ91D镁合金进行激光熔凝,建立了熔凝温度场有限元模型,分析了激光熔凝过程温度场加热冷却的规律,并通过试验验证模型的准确性。分别采用扫描电镜、显微硬度计、共聚焦激光扫描显微镜及摩擦磨损试验机分析了激光熔凝层的形貌、硬度及摩擦学特性。结果表明:激光熔凝温度场呈动态分布,表现出典型的急热骤冷特征,激光熔凝层显微硬度由表及里呈梯度分布,较好地验证了激光熔池的深度,熔凝层显微硬度均值为基体的1.4倍;激光熔凝层磨损量仅为基体的1/3,耐磨性较基体大幅提高,熔凝层及基体的磨损机制主要为磨粒磨损。Laser surface remelting of AZ91 D magnesium alloy was conducted,and the finite element model of the temperature field of Mg alloy laser surface remelting was established.The law of heating and cooling of the temperature field during laser remelting was analyzed,and the accuracy of the established model was verified by experiment. In the meantime,a scanning electron microscope,a microhardness meter,a cofocal laser scanning electron microscope,and a friction and wear tester were separately performed to analyze the morphology,hardness,and friction and wear behavior of as-prepared laser surface remelting coating. Results indicated that the temperature field of the laser surface remelting of Mg alloy exhibited dynamic distribution as well as sharp heating and condensation characteristics. Besides,the microhardness of the laser surface remelting coating was dominated by gradient distribution from the surface to the Mg alloy substrate,which well corresponded to the depth of the laser molten pool. Moreover,the average microhardness of the laser surface remelting coating was 1. 4 times as much as that of the Mg alloy substrate,while its wear volume loss was only 1 /3 as much as that of the substrate. This meant that the laser surface remelting coating,dominated by abrasive wear,exhibited much better wear resistance than the Mg alloy substrate.

关 键 词：激光熔凝 AZ91D镁合金 温度场 数值模拟 摩擦学性能 

分 类 号：TG178[金属学及工艺—金属表面处理]