激光熔覆Ni基B4C合金涂层的组织与性能研究

利用5kW连续波CO2激光器对16Mn钢基材表面预置的含20 vol%B4CP的Ni基合金复合粉末进行激光熔覆得到Ni基B4C合金涂层(NiB4c),研究了NiB4c涂层的组织形貌与相组成,并用单纯的镍基合金涂层(Ni60)进行了显微硬度及滑动磨损性能的对比试验。结果表明,NiB4C涂层由涂层下部的胞状晶和涂层中上部的树状枝晶及其间的共晶组织所组成,其组成相为γ-Ni,γ-(Ni,Fe)固溶体和(Cr,Fe)7C3,CrB,Ni3B,Fe2B,Fe23(C,B)6等化合物,涂层中存在未熔的B4C颗粒。激光熔覆NiB4c涂层比Ni60涂层具有较高的硬度和耐磨性,并分析了NiB4C涂层的强化机理。

Microstructure and Performance of Laser Clad Ni-based Alloy Coating with B4C Ceramics Particles

Laser clad Ni -based alloy coating with 20vol% B4CP(NiB4C) on 16Mn steel substrate has been obtained by 5kW CO2 continuous wave laser. Microstructure and phase constitutes of the NiB4C coating have been studied, and micro - hardness and the performance of sliding wear of the NiB4C coating have been discussed in contrast to laser clad Ni - based alloy coating (Ni60). The result shows that the microstructure of NiB4C coating is consisted of cellular structures in bottom of the NiB4C coating and dendritic ysolid solution plus the eutectic structure between the dendrites in the middle and top of the NiB4C coating. Constituent phases of the NiB4C coating mainly have y - Ni,y - (Ni, Fe) , (Cr,Fe)7C3, CrB, Ni3B, Fe2B and Fe23(C, B)6. B4C Ceramics Particles exist between the dendrites and not totally melted. Micro - hardness and sliding wear resistance of NiB4C coating are higher than that of the Ni60 coating. The strengthen mechanism of the NiB4C coatings is analyzed.