Influences Of Precursor Constitution And Processing Speed On Microstructure And Wear Behavior During Laser Clad Composite Coatings On γ-tial Intermetallic Alloy

摘要

The effects of constitution of precursor mixed powders and scan speed on microstructure and wear properties were designed and investigated during laser clad γ/Cr_7C_3/TiC composite coatings on γ-TiAl intermetallic alloy substrates with NiCr-Cr_3C_2 precursor mixed powders. The results indicate that both the constitution of the precursor mixed powders and the beam scan rate have remarkable influence on microstructure and attendant hardness as well as wear resistance of the formed composite coatings. The wear mechanisms of the original TiAl alloy and laser clad composite coatings were investigated. The composite coating with an optimum compromise between constitution of NiCr-Cr_3C_2 precursor mixed powders as well as being processed under moderate scan speed exhibits the best wear resistance under dry sliding wear test conditions.