*Article* **Influence of Specific Energy on Microstructure and Properties of Laser Cladded FeCoCrNi High Entropy Alloy**

### **Leilei Wang 1,\*, Zhuanni Gao 1, Mengyao Wu 1, Fei Weng 2, Ting Liu 1 and Xiaohong Zhan 3,\***


Received: 21 September 2020; Accepted: 29 October 2020; Published: 2 November 2020

**Abstract:** Specific energy is a key process parameter during laser cladding of high entropy alloy (HEA); however, the e ffect of specific energy on the microstructure, hardness, and wear resistance of HEA coating has not been completely understood in the literature. This paper aims at revealing the influence of specific energy on the microstructure and properties of laser cladded FeCoCrNi high entropy alloy on the Ti6Al4V substrate, and further obtains feasible process parameters for preparation of HEA coating. Results indicate that there are significant di fferences in the microstructure and properties of the coatings under di fferent specific energy. The increase of specific energy plays a positive role in coarsening the microstructure, promoting the di ffusion of Ti from the substrate to HEA coating, and subsequently a ffects the hardness of samples. The HEA coating is mainly composed of the face-centered cubic phase and body-centered cubic phase, precipitating a small amount of Fe-Cr phase and Laves phase. Metallurgical bonding is obtained between the base metal and the coatings of which the bonding region is mainly composed of columnar crystal and shrinkage cavities. The microhardness of the HEA coating reaches 1098 HV, which is about 200% higher than that of the TC4 substrate, and the wear resistance is significantly improved by the HEA coating.

**Keywords:** laser cladding; high entropy alloy; specific energy; phase transformation; wear resistance
