Laser synthesis of titanium aluminides matrix composite coatings reinforced by in-situ titanium carbide particles on Ti-6Al-4V substrate

Abstract

Ti-6Al-4V is one of the most widely used titanium alloys in aerospace and civil applications. It is a pity that the wear resistance and elevated temperature properties of this alloy are relatively poor. Today titanium aluminides are becoming the most attractive light-weight high temperature structure materials. And the titanium aluminides matrix composites are growing into a hotspot. In this paper, laser cladding experiments have been conducted on Ti-6Al-4V substrate in order to synthesize titanium aluminides matrix composite coatings reinforced by in-situ titanium carbide particles. Laser cladding with different compositions of the powder mixture containing titanium, aluminum, carbon and other elements was implemented by preplacing powder beds and coaxial powder feeding. The results showed that the fine coatings with few pores and no cracks can be obtained by laser cladding. There were titanium aluminides and a great number of in-situ titanium carbide particles in the coatings. The microhardness of these coatings can reach HV0.2650-750, which is much higher than that of the substrate. So these coatings will increase wear resistance of the substrate alloy greatly. Furthermore, adding of carbon powder into titanium/aluminum powders can make clad layer better than adding titanium carbide powder directly.Ti-6Al-4V is one of the most widely used titanium alloys in aerospace and civil applications. It is a pity that the wear resistance and elevated temperature properties of this alloy are relatively poor. Today titanium aluminides are becoming the most attractive light-weight high temperature structure materials. And the titanium aluminides matrix composites are growing into a hotspot. In this paper, laser cladding experiments have been conducted on Ti-6Al-4V substrate in order to synthesize titanium aluminides matrix composite coatings reinforced by in-situ titanium carbide particles. Laser cladding with different compositions of the powder mixture containing titanium, aluminum, carbon and other elements was implemented by preplacing powder beds and coaxial powder feeding. The results showed that the fine coatings with few pores and no cracks can be obtained by laser cladding. There were titanium aluminides and a great number of in-situ titanium carbide particles in the coatings. The microhardness of these...