不同功率下激光重熔对Mg-Zn-Y-Zr合金性能的影响研究  

Effect of Laser Remelting on Properties of Mg-Zn-Y-Zr Alloy at Different Powers

作　　者：刘月洋 高士友[1] 周英才 刘迪 韦亚南 Liu Yueyang;Gao Shiyou;Zhou Yingcai;Liu Di;Wei Yanan(College of Mechanical Engineering,Yanshan University,Qinhuangdao,Hebei 066004,China)

机构地区：[1]燕山大学机械工程学院,河北秦皇岛066004

出　　处：《光学学报》2020年第6期104-114,共11页Acta Optica Sinica

基　　金：国家自然科学基金(51375425)。

摘　　要：由于镁合金耐磨及硬度性能较差,应用激光重熔技术进行表面改性就显得尤为必要,其中激光功率因素所产生的影响十分显著。为了探究激光重熔中功率因素对稀土镁合金的微观组织结构,硬度以及摩擦磨损性能的影响。通过使用3kW的DILAS半导体激光器对Mg-1.85Y-7.91Zn-0.75Zr(质量分数,%)合金进行不同功率下的激光重熔实验。采用光学显微镜(OM),电子扫描显微镜(SEM),X射线衍射仪(XRD)和能谱仪(EDS)观察所制得试样的组织,形貌,相成分及分布;使用显微硬度计测量维氏硬度;使用摩擦磨损试验机测试样品的摩擦磨损性能,从而得出不同激光功率对组织,性能的影响。研究表明,经过重熔处理的合金宏观凝固组织明显细化,且随着功率升高,晶粒变大,第二相分布愈加弥散。由于细晶强化,固溶强化以及弥散强化的影响导致了硬度和耐磨性提高,其中800,1000,1200,2000W激光功率作用下重熔细晶区的维氏硬度平均值分别为90.97,93.47,94.20,95.53HV,而粗晶基材区的维氏硬度平均值仅为63.90HV,2000W功率作用下的硬度照比基材提升了49.50%。随着功率的升高,耐磨性越高且逐渐从以黏着磨损为主过渡到以磨粒磨损为主。可见,激光重熔技术可以明显强化该稀土镁合金,激光功率的增大可以显著增加该合金的硬度以及抗摩擦磨损性能。Because of the poor wear resistance and low hardness of magnesium alloys,the modification of their surface using laser remelting technology is particularly beneficial,especially,the influence of the laser power factor is important.To investigate the influence of the power factor in laser remelting on the microstructure,hardness,and friction and wear properties of rare-earth magnesium alloys,the laser remelting experiments with Mg-1.85Y-7.91Zn-0.75Zr(mass fraction,%)alloy were conducted under different laser powers using a 3kW DILAS semiconductor laser.The structure,morphology,phase composition,and distribution of the samples were observed by optical microscopy(OM),scanning electron microscopy(SEM),X-ray diffraction(XRD),and energy-dispersive spectroscopy(EDS).Microhardness tests were conducted to measure the Vickers hardness and elucidate the effects of different laser powers on the structure and mechanical properties of the alloy.The results show that the macrostructure of the alloy after the remelting process becomes finer and with increasing laser power,the grain increases and the second phase becomes more dispersed.Hardness and wear resistance are enhanced because of finegrained strengthening,solid solution strengthening,and dispersion strengthening.Among the changes,under laser powers of 800,1000,1200,and 2000W,the average Vickers hardness values of the remelted fine crystal region are 90.97,93.47,94.20,and 95.53,respectively,whereas the average Vickers hardness value of the coarse crystal base material is only 63.90.When the alloy is laser-remelted under a power of 2000W,it exhibits a hardness 49.50%greater than that of the base material.As the power is increased,the wear resistance is enhanced and the wear gradually transitions from adhesive to abrasive wear.The laser remelting technology substantially strengthens the rare-earth magnesium alloy,and increasing the laser power can dramatically increase the hardness,antifriction,and antiwear properties of the alloy.

关 键 词：激光光学 MG-ZN-Y-ZR合金 硬度 摩擦磨损 耐磨性 

分 类 号：TN249[电子电信—物理电子学] TG146.22[一般工业技术—材料科学与工程]