Influence mechanism of WC particle content on wear resistance of TC4 laser deposition

Abstract:

A In view of the poor wear resistance of TC4 titanium alloy, laser melting deposition technology (LMD) was used to fabricate a 2mm thick wear resistant cladding coating of composite powder (3~5μmWC and 53~150μmTC4) by synchronous powder feeding method. Optical microscope (OM) and scanning electron microscope (SEM) were used to observe and analyze the microstructure and elemental composition of the cladding layer. The wear properties of the cladding layer were tested and its wear mechanism was analyzed under the condition of dry friction reciprocating sliding at room temperature. The results show that the cladding coating has good adhesion to the substrate and no obvious cracks, pores and other defects. With the increase of WC particle mass fraction, (Ti,W)C_1-x increases gradually and distributes at α/β phase boundary and grain boundary. The average hardness of cladding layer is 34% higher than that of matrix, and the hardness is up to 1.49 times of matrix. The wear volume and wear coefficient of the cladding layer change in the same way, decreasing first, then increasing and then decreasing. The wear is abrasive wear, and the wear coefficient is close to the base material.The wear rate decreases with the increase of WC particle mass fraction. When WC content is 10%, the wear resistance of cladding layer is the best, which is 25% higher than that of base material.

Key words:Laser melting deposition; Titanium alloy; Particle reinforcement; Microstructure; Wear-resisting performance