汽车用AZ91镁合金的表面改性与性能研究  

Study on surface modification and properties of AZ91 magnesium alloy for automotive applications

作　　者：和豪涛[1] 吴笑伟[1] 李金辉 He Haotao;Wu Xiaowei;Li Jinhui(School of Automobile,Henan College of Transportation,Zhengzhou 450005,China;School of Vehicle and Traffic Engineering,Henan University of Science and Technology,Luoyang 471003,China)

机构地区：[1]河南交通职业技术学院汽车学院,河南郑州450005 [2]河南科技大学车辆与交通工程学院,河南洛阳471003

出　　处：《电镀与精饰》2023年第12期1-7,共7页Plating & Finishing

基　　金：河南省科技攻关计划项目(2102210237)。

摘　　要：为了提升汽车用AZ91镁合金的表面耐磨性和耐蚀性,采用激光熔覆的方法在AZ91镁合金基体表面制备了A+x wt.%(Zr+B_(4)C)熔覆层(x=8、16和24),研究了(Zr+B_(4)C)含量对熔覆层物相组成、显微形貌、硬度、耐磨和耐蚀性能的影响。结果表明,Al+8 wt.%(Zr+B_(4)C)熔覆层由Al_(12)Mg_(17)、Al_(3)Mg_(2)、Al_(9.83)Zr_(0.17)、ZrC和AlB_(2)组成,提升(Zr+B_(4)C)含量至16%和24%时,熔覆层中还形成了Al_(3)Zr相,且(Zr+B_(4)C)含量越大熔覆层中ZrC相含量更高。3种激光熔覆层和过渡区的硬度都高于AZ91镁合金基体;在距离熔覆层表面相同距离时,Al+16 wt.%(Zr+B_(4)C)熔覆层的硬度要高于Al+8 wt.%(Zr+B_(4)C)熔覆层。3种激光熔覆层的最大摩擦系数和平均摩擦系数都小于AZ91镁合金基体,且磨损率都小于AZ91镁合金基体;3种熔覆层的耐腐蚀性能都优于AZ91镁合金基体,(Zr+B_(4)C)含量为16%和24%时熔覆层的耐腐蚀性能相当,且优于(Zr+B_(4)C)含量为8%的熔覆层。Al+x wt.%(Zr+B_(4)C)熔覆层中适宜的(Zr+B_(4)C)含量为16%,此时熔覆层具有较高的硬度、耐磨性和耐腐蚀性能。In order to improve the surface wear resistance and corrosion resistance of AZ91 magnesium alloy for automobiles,Al+x wt.%(Zr+B_(4)C)cladding layers(x=8,16,and 24)were prepared on the surface of AZ91 magnesium alloy substrate using laser cladding.The effects of(Zr+B_(4)C)content on the phase composition,microstructure,hardness,wear resistance,and corrosion resistance of the cladding layer were studied.The results show that the Al+8 wt.%(Zr+B_(4)C)cladding layer consists of Al_(12)Mg_(17),Al_(3)Mg_(2),Al_(9.83)Zr_(0.17),ZrC,and AlB_(2),when the(Zr+B_(4)C)content is increased to 16%and 24%,Al_(3)Zr phase is also formed in the cladding layer,and the higher the(Zr+B_(4)C)content,the higher the ZrC phase content in the cladding layer.The hardness of the three laser cladding layers and transition zones is higher than that of the AZ91 magnesium alloy matrix.At the same distance from the surface of the cladding layer,the hardness of Al+16 wt.%(Zr+B_(4)C)cladding layer is higher than that of Al+8 wt.%(Zr+B_(4)C)cladding layer.The maximum and average friction coefficients of the three laser cladding laydoiers are lower than those of the AZ91 magnesium alloy matrix,and the wear rate is smaller than that of the AZ91 magnesium alloy matrix.The corrosion resistance of the three types of cladding layers are better than that of the AZ91 magnesium alloy matrix,when the content of(Zr+B_(4)C)is 16%and 24%,the corrosion resistance of the cladding layer is equivalent,and better than that of the cladding layer with a content of(Zr+B_(4)C)of 8%.The appropriate content of(Zr+B_(4)C)in the Al+x wt.%(Zr+B_(4)C)cladding layer is 16%,when the cladding layer has high hardness,wear resistance,and corrosion resistance.

关 键 词：AZ91镁合金 激光熔覆 Zr+B_(4)C含量 显微形貌 性能 

分 类 号：TG665[金属学及工艺—金属切削加工及机床]