Research status and prospects of refractory high-entropy alloys prepared by selective laser melting

With advantages of high melting point,high hardness and high-temperature phase structure stability,Refractory High-Entropy Alloys(RHEAs)have become important materials in the fields of aerospace,marine and nuclear energy industries. This paper presents a systematic review of different systems of RHEAs prepared by Selective Laser Melting(SLM)technology,and analyses the microstructure,mechanical properties,residual stress and corrosion resistance of SLM. The results show that the RHEAs prepared by SLM have not changed the intrinsic phase (BCC phase),the dendritic crystal morphology is dendritic,equiaxed,and cytosolic,and the grain size has been reduced by an average of 80%–90% compared with that of conventional arc melting. The results also show strengthening mechanisms such as fine grain strengthening and solid solution strengthening caused by grain refinement effectively enhance the mechanical properties of the materials. In the preparation of RHEAs by SLM technology,the residual stress accumulation caused by local heating and cooling of the heat source can be reduced by optimizing the process parameters and preheating the base metal;SLM can achieve uniform distribution of refractory elements,and the refined grains can increase the grain boundary density,reduce intergranular corrosion,and enhance the corrosion resistance of the alloy. © 2024 Chinese Society of Astronautics. All rights reserved.