Microstructure and wear behavior of mechanically alloyed powder AlxMo0.5NbFeTiMn2 high entropy alloy coating formed by laser cladding

Abstract

High entropy alloys (HEAs) is a newly wear-resistant material with multi-component structures of equal or near equal ratio. The tensile strength of pure Al is one fifth of the low carbon steel. After heat treatment and alloying, the strength will be greatly increased. Al alloys have good machining performance. The secondary and bending machining are also easier to obtain. To strengthen the wear resistance and hardness of normal steel tools, AlxMo0.5NbFeTiMn2 (x = 1, 1.5, 2) HEA coatings are experimentally manufactured in a systematic approach to complete existing results and prove an effective method of HEA coating preparation by laser cladding. The powders were first mechanically alloyed by a high-energy rod mill to ensure the homogenization of the structure. The structural characteristics were studied by XRD measurement, resulting in the crystal structure and its role in the HEA sample can be determined. Phase composition determined by electron microscope measurement (EDS, EBSD and TEM). It was found that their appearance, composition and contribution in the studied HEAs depended on the Al content. The phase composition of the coating consists of body-centered-cubic solid solution as well as (Nb, Ti)C carbides. As a result, the Al2Mo0.5NbFeTiMn2 HEA coating shows the highest microhardness and most excellent wear resistance of all tested coatings. Compared with the substrate, this indicates the smoother worn surface and lower volume wear rates can be concluded with Al addition in HEA coatings. It is assumed to be promising for a fusion alloy progress standpoint.