Research on the microstructure and wear resistance of titanium alloy structural members repaired by laser cladding

Aero-engine overhaul calls for low-cost and high-quality method to solve the failure of structural members. This paper presents a pulsed-laser cladding (repair coating) of near alpha titanium alloy used for structural member repairing and investigates the microstructures, microhardness and wear resistance of the repair coating. The repair coating is mainly composed of alpha' martensite. The center region of the melting zone formed by each single pulse is characterized by micro-acicular martensite. At the margin, the microstructure shows columnar morphology. With a simplified model of laser cladding, the formation of columnar morphology is discussed. Compared with the substrate, the repair coatings show near performances on microhardness and wear resistance, and decrease the wear of lining pads dramatically in same condition. The different performances between repair coatings and substrate are mainly attributed to the different microstructures and the diffusive behaviors of 0, C, and other elements. The results above indicate that, it is feasible to repair the near alpha titanium alloy structural members by pulse-laser cladding. (C) 2008 Elsevier Ltd. All rights reserved.