Tuning the mechanical properties of powder bed fusion printed CoCrFeNiMn high-entropy alloys by annealing and hot isostatic pressing

Powder bed fusion (PBF) and other additive manufacturing (AM) techniques show good potential for re-search and the processing industry. The reinforcement on the microstructure and mechanical properties is a practical necessity of additive manufacturing (AM) processed high-entropy alloy (HEA), which has struc-tural and performance defects for application. Two post thermal treatment approaches based on annealing and hot isostatic pressing (HIP) for PBF technology printed CoCrFeNiMn HEA are proposed to enhance mechanical properties. No additional phase is detected by X-ray diffraction when the printed alloy un-dergoes post thermal processing, in addition to the face-centred-cubic crystalline phase. Both approaches give rise to almost fully dense arrangement structure with relative density exceeding 98%. Post treatments can significantly enhance the plasticity of PBF printed HEAs; in particular, they can lead to considerable increment in elongation and tensile properties, which can be attributed to the main mechanism of the synergistic effect of dislocation and nano-twin crystal deformation. In summary, both post thermal treat-ments are of great significance to the development of HEA with excellent mechanical properties. In parti-cular, HIP leads to optimal structure and performance.(c) 2023 Elsevier B.V. All rights reserved.