铝合金激光熔覆Ni-WC涂层的组织及耐磨性

采用５ｋＷＣＯ２激光器，对ＺＡ１１１合金表面的Ｎｉ－ＷＣ等离子涂层进行了熔覆处理。利用ＳＥＭ和Ｘ射线衍射分析了激光层中的组织分布，并对激光处理后的试样进行了耐磨性实验。实验结果表明，激光熔层中的组织以镍铝基的金属间化合物Ａｌ３Ｎｉ，Ａｌ３Ｎｉ２，ＡｌＮｉ和Ｎｉ３Ａｌ为主；ＷＣ颗粒基本在熔区中熔化，在冷却过程中以弥散碳化物形式析出。这些组织的存在使得激光熔层具有很高的硬度，其润滑磨损耐磨性为未经激光处理喷涂层的１．７５倍和Ａｌ－Ｓｉ合金基体的２．８３倍。

Microstructure and Wear Resistance of Laser Cladding Ni WC Coating on Aluminum Alloy

A plasma sprayed Ni WC coating was cladded on the ZA111 alloy surface by a 5 kW CO 2 laser. Using SEM and X ray analyses, the microstructure of the laser melted zone was investigated, and the wear resistance of the laser treated samples was measured. Experimental results showed that the Ni Al intermetallic compounds Al 3Ni, Al 3Ni 2, AlNi and Ni 3Al are dominant in the laser melted zone. Meanwhile, some WC particles were melted during the laser melting, and they separated in carbides during the cooling. The microhardness is very high in the laser melted zone. The wear resistance of laser melted samples is 2.83 times high than the aluminum matrix and 1.75 times high than plasma sprayed samples.