Microstructures and Wear Resistance of CoCrFeNi2V0.5Tix High-Entropy Alloy Coatings Prepared by Laser Cladding

Yaning Li,Zhiqiang Cao,Hui Liang,Hui Jiang,Qiuxin Nie,Dewei Deng,Zhaoxin Qi

doi:10.3390/cryst10050352

Abstract

CoCrFeNi2V0.5Tix high entropy alloy coatings were synthesized by laser cladding on Ti-6Al-4V (annotated as TC4) substrate. The microstructures, hardness, and wear properties of the coatings were studied in detail. The results showed that these coatings were all composed of body-centered cubic (BCC) solid solution, (Co,Ni)Ti2 phase, and Ti-rich phase. With the increase of Ti content (x in the range of 0–1.0), the hardness of these coatings (about 960 HV) was basically unchanged and stabilized, whereas, when x was increased to 1.25, the correspondent hardness was decreased significantly to about 830 HV. Compared with original substrate, the wear resistance of high-entropy alloy (HEA) coatings was greatly improved. In particular, CoCrFeNi2V0.5Ti0.75 (donated as Ti0.75) exhibited the lowest wear rate, width, and depth of tracks of wear, indicating the best wear resistance. Moreover, the wear mechanisms of Ti0.75 coating were mainly adhesive wear and oxidative wear.

Highlights

The titanium alloys with low density, high specific strength, and good high temperature properties play a crucial role in many fields, especially aerospace and weapons [1]
The results showed that the FeCrCoNiAlMo1.0 high-entropy alloy (HEA) coating displayed the highest microhardness and smallest wear rate
The following formula is usually used to calculate the mixing enthalpy of the HEAs system according to i=1,i, j the known binary data from [34,35]

Summary

Introduction

The titanium alloys with low density, high specific strength, and good high temperature properties play a crucial role in many fields, especially aerospace and weapons [1]. The elastic modulus of TC4, E = 110 GPa, is about half of that of steel and its specific strength is. The total amount of TC4 alloy used in aircraft structural materials can reach 80% of the total amount of titanium alloy. Owing to the poor wear resistance, the industrial application of the TC4 titanium alloy is still greatly limited [2,3]. It is important to improve the surface properties of TC4 titanium alloys to meet the requirements in various complex service environments and broaden their application range

Methods

Results

Conclusion