激光熔覆MoSi_2-NiCrSiB复合涂层的组织和性能

Microstructure and Property of Mo Si_2-Ni Cr Si B Composite Coating by Laser Cladding

在GH4169表面通过激光熔覆制备不同成分配比的Mo Si2-Ni Cr Si B复合涂层,利用扫描电镜对熔覆层的微观组织进行观察,测试了熔覆层的显微硬度及高温抗氧化性能。结果表明:添加不同比例的镍基合粉末制备的Mo Si2-Ni Cr Si B复合涂层试样与基体形成良好的冶金结合,无明显的裂纹、空洞,且随镍基合金粉末的添加,熔覆层组织与基体的结合越来越紧密,树枝晶状的硅钼相与合金相交错分布。添加不同比例镍基合金粉末时复合涂层的显微硬度比基体都有所提高,最高可达540 HV0.2,是基体硬度的1.2倍,随镍基合金粉末的增多,复合涂层硬度降低,最多会降低11%。添加10%的镍基合金粉末时试样的高温抗氧化性能最好。

Mo Si2-Ni Cr Si B composite coating on superalloy 4169 was prepared by laser cladding using powders of different proportions. Microstructure was investigated through SEM. Microhardness and high temperature oxidation resistance were also researched. The experimental results show that Mo Si2-Ni Cr Si B composite coating developes good metallurgical bonding with substrate by adding different proportions of Nickel-based powders, no obvious cracks and holes. The binding of cladding coating and substrate becomes more close with the increase of Nickel-based powers, dendritic silicon molybdenum phase and alloy phase staggeres distribution. Microhardness of Mo Si2-Ni Cr Si B composite coartings increases by adding different proportions of Nickel-based powers, up to 540 HV0.2, 1.2 times of microhardness of substrate. The microhardness of Mo Si2-Ni Cr Si B composite coating reduces in pace with the increase of Nickel-based powers by 11%. High temperature oxidation resistance of the sample is the best, when the cladding powders included 10% Nickel-based powers.