(1. 太原理工大學 材料科學與工程學院，太原 030024；
2. 太原理工大學 新材料界面科學與工程教育部重點實驗室，太原 030024)
摘 要: 針對鎂合金表面耐磨性和耐蝕性差的問題，利用橫流CO2激光器在AZ31B鎂合金表面激光熔覆Cu-Ni合金層，并利用光學顯微鏡(OM)、掃描電鏡(SEM)和能譜分析儀(EDS)分析熔覆層與基體的結(jié)合界面特征以及顯微組織和成分分布情況，測試合金層的顯微硬度和耐蝕性。結(jié)果表明：合金層與基體結(jié)合良好，缺陷較少，但局部存在不均勻的Cu-Ni富集區(qū)，且在其邊緣區(qū)域的枝晶間均勻分布著1~1.5 µm的十字狀Laves相；合金層的硬度分布比較均勻，約為75HV0.05，明顯高于基體的顯微硬度45HV0.05；Cu-Ni合金層比AZ31B鎂合金基體的腐蝕電位正移317 mV，腐蝕電流降低78 mA/cm2，耐蝕性也得到較大改善。
關鍵字: AZ31B鎂合金；Cu-Ni合金層；激光熔覆；耐磨性；耐蝕性
（1. College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
2. Key Laboratory of Interface Science and Engineering in Advanced Materials of Ministry of Education,
Taiyuan University of Technology, Taiyuan 030024, China）
Abstract:To improve the wear resistance and corrosion resistance of the surface of magnesium alloy, the laser alloying experiment was carried out on the AZ31B magnesium alloy with pre-placed Cu-Ni powder using transverse flow CO2 laser. The microstructures, interface features and composition distribution of laser cladding layer were studied through OM, SEM and EDS. The results show that the Cu-Ni cladding layer and the substrate achieve a good metallurgical bonding without obvious defects. But there is uneven local Cu-Ni-rich region, and cross-like Laves phases with size of 1−1.5 μm evenly distribute between dendrites and in their edge regions. The microhardness of Cu-Ni cladding layer is more evenly distributed, about 75HV0.05, significantly higher than the matrix hardness (45HV0.05). Compared with AZ31B magnesium alloy, the corrosion potential of Cu-Ni alloy layer is shifted by 317 mV and corrosion current is reduced by 78 mA/cm2.
Key words: AZ31B magnesium alloy; Cu-Ni alloy layer; laser cladding; wear resistance; corrosion resistance
