Effect of ultrasonic solid-liquid dual-phase conduction on microstructure and properties of Ti-based underwater wet laser deposition layer

Abstract

Underwater wet laser deposition is a technology of great importance for the online emergency repairs of underwater equipment. In this study, ultrasonic solid-liquid dual-phase conduction (USLC) was used to assist in the preparation of TiC in-situ reinforced Ti-based underwater wet laser deposition layer. The formation mechanism, microstructure, phase composition, microhardness, and tribology properties of the underwater deposition layer before and after the USLC were comprehensively analyzed and evaluated. The results indicated that the dilution rate of the USLC-assisted underwater laser deposition (U-ULD) layer increases to 71.72 % compared with that of the underwater laser deposition layer (49.04 %). The USLC treatment can promote the degassing process and reduce the porosity defects of underwater laser deposition by the transient cavitation effect. And the USLC treatment promoted the globularization and refinement of the TiC in-situ reinforced phase and caused the granular TiC in-situ reinforced phase in a discontinuous reticular distribution. The average microhardness of the U-ULD layer was 548.4 ± 15.5 HV0.3. The synergistic effects of the discontinuous reticular distribution of TiC particles and the abrasive chips of TiC and TiO2 significantly enhanced the friction properties of the U-ULD layer. The U-ULD layer had the lowest coefficient of friction, with an average coefficient of friction of 0.16. Noticeably, the friction mechanism of the U-ULD layer demonstrated the feasibility of USLC treatment to enhance the friction property of the underwater wet laser deposition. It can provide a new technique to improve the surface properties of titanium-based alloy underwater wet laser deposition.