Effect of Cr on Microstructure and Properties of WVTaTiCrx Refractory High-Entropy Alloy Laser Cladding

Abstract

WVTaTiCrx (x = 0, 0.25, 0.5, 0.75, 1) refractory high-entropy alloy coatings were prepared on a 42-CrMo steel plate using laser cladding. The purpose of this work is to investigate the effect of the Cr content on the microstructure and properties of the WVTaTiCrx coating. The morphologies and phase compositions of five coatings with different Cr contents were comparatively observed. In addition, the hardness and high-temperature oxidation resistance of the coatings were also analyzed. As a result, with the increase in Cr, the coating grains were more refined. All the coating is mainly composed of the BCC solid-solution phase, which promotes the precipitation of the Laves phase with the increase in Cr. The addition of Cr greatly improves the hardness, high-temperature oxidation resistance and corrosion resistance of the coating. The WVTaTiCr (Cr1) exhibited superior mechanical properties, especially in terms of its exceptional hardness, high-temperature oxidation resistance and outstanding corrosion resistance. The average hardness of the WVTaTiCr alloy coating reaches 627.36 HV. After 50 h of high-temperature oxidation, the oxide weight of WVTaTiCr increases by 5.12 mg/cm2, and the oxidation rate is 0.1 mg/(cm2·h). In 3.5 wt% NaCl solution, the corrosion potential of WVTaTiCr is −0.3198 V, and the corrosion rate is 0.161 mm/a.

Effects of Alloying Elements and Mechanical Alloying on Characteristics of WVTaTiCr Refractory High-Entropy Alloys

“…This suggests that the large number of Ti-rich or Ta-rich oxide particles that formed on the BCC matrix are the primary second phase of the sample. In addition, the WVTaTiCr model alloy has a hardness value of 638 HV, which is a similar result to the literature data for the same alloy system (627.36 HV) [14]. The presence of oxide particles can act as a dispersion strengthening on the materials, thus increasing the hardness of the alloy.…”

“…Refractory metal elements with low activation are beneficial for the design of nuclear structural materials. It has been reported that the W, Ta, Ti, V, and Cr elements have low neutron activation properties and are suitable for the development of a new RHEA for fusion plasma-facing materials [ 14 , 15 ]. WTaTiVCr high-entropy alloys with enhanced physical and mechanical characteristics can be achieved by a powder metallurgical technique [ 15 ].…”

Laser Processing and Multi-Energy Field Manufacturing of High-Performance Materials

“…In addition, Xu et al [2] investigated the effects of the Cr content on the microstructure and properties of the WVTaTiCr x (x = 0, 0.25, 0.5, 0.75, 1) coating. The trends in the coating's microstructure, hardness, high-temperature oxidation resistance, and corrosion resistance were analyzed by varying the Cr content.…”