TiAl合金激光熔覆复合材料涂层耐磨性研究

Study on wear resistance of laser clad composite coatings on TiAl intermetallic alloy

利用预涂NiCrCr3C2复合粉末对γTiAl合金(简称TiAl合金)进行激光熔覆处理,制得了以Cr7C3、TiC硬质相为耐磨增强相,以γNiCrAl镍基固溶体为基体的复合材料涂层,研究了原始TiAl合金和激光熔覆涂层的室温和高温(600℃)滑动磨损性能,并讨论了原始TiAl合金和所制备涂层的室温和高温滑动磨损机理。结果表明:激光熔覆复合材料涂层均具有较好的室温和高温滑动磨损耐磨性。室温下涂层的耐磨性先随着其中硬质耐磨增强相体积分数的增加而提高,但当耐磨相体积分数过高时,由于涂层脆性增大,其耐磨性反而下降。

γ-NiCrAl/Cr_7C_3/TiC composite coatings were fabricated on γ-TiAl intermetallic alloy by laser cladding with NiCr-Cr_3C_2 precursor mixed powders. Room and high-temperature(600℃) full dry sliding wear behaviors of the original TiAl alloy and laser clad composite coatings have been investigated and the corresponding wear mechanisms are discussed. Results show that higher wear-resistance of the clad composite coatings than that of the original TiAl alloy is achieved under both room and high temperature full dry slidng wear conditions. Room temperature sliding wear resistance of the composite coatings increases with the increasing amounts of Cr_3C_2 powders in the NiCr-Cr_3C_2 precursor mixed powders firstly,and then decreases when the amount of Cr_3C_2 powders is over a critical value because of the brittleness of the whole composite coating.