# Tailoring Microstructure and Properties of CoCrNiAlTiNb High-Entropy Alloy Coatings via Laser Power Control During Laser Cladding

## TL;DR

This study shows how adjusting laser power during coating fabrication can improve the durability of high-entropy alloy coatings used in hydraulic machinery.

## Contribution

The study demonstrates precise laser power control optimizes cavitation erosion resistance in high-entropy alloy coatings.

## Key findings

- Coating microhardness decreased from 345.3 HV0.2 as laser power increased from 3000 W to 3400 W.
- The 3000 W coating showed 13.5% lower wear rate and 16.07% higher wear resistance than the 3200 W coating.
- The 3000 W coating had 88.89% less mass loss in cavitation erosion tests compared to the substrate.

## Abstract

To enhance the operational damage resistance of hydraulic machinery, this study employed laser cladding technology to fabricate a Co37.4Cr30Ni20Al5Ti5Nb2.6 high-entropy alloy coating on 04Cr13Ni5Mo substrate. The influence of laser power on the microstructure and properties of the coating was systematically investigated. Based on preliminary research, the friction-wear performance and cavitation erosion behavior of the coatings prepared at 3000 W, 3200 W, and 3400 W were specifically examined. Results indicate that as the laser power increased from 3000 W to 3400 W, the microhardness of the coating gradually decreased from 345.3 HV0.2. At 3000 W, the precipitation of trace strengthening phases significantly enhanced the mechanical properties. In wear tests under a 20 N load for 30 min, the wear rate of the coating prepared at 3000 W was 1.41 × 10−4 mm3/(N·m), which is 13.5% lower than that of the 3200 W coating (1.63 × 10−4 mm3/(N·m)) and 16.07% higher in wear resistance compared to the substrate. Cavitation erosion tests revealed that after 20 h of ultrasonic vibration, the mass loss of the 3000 W coating was only 2.35 mg, representing an 88.89% reduction compared to the substrate (21.15 mg), and significantly lower than that of the 3200 W (4.57 mg) and 3400 W (3.85 mg) coatings. This study demonstrates that precise control of laser power can effectively optimize the cavitation erosion resistance of high-entropy alloy coatings, providing technical support for their application in harsh environments.