Effect of solution heat treatment and hot isostatic pressing on the microstructure and mechanical properties of Hastelloy X manufactured by electron b eam powder bed fusion

Prior to the application of AM components for critical applications, it is necessary to have a better understanding of the effect of different post-fabrication treatments on the microstructure and mechanical properties of such parts. In this study, efforts were made to achieve an in-depth understanding of the effect of post-fabrication Solution Heat Treatment (SHT) and Hot Isostatic Pressing (HIP) on the microstructure and mechanical properties of Hastelloy X parts built by electron beam powder bed fusion (PBF-EB) process. The effects of SHT and HIP on porosity, microstructure, texture and mechanical properties have been investigated and compared with that of as-built PBF-EB Hastelloy X. Post-fabrication HIP treatment led to a significant reduction in the porosity content, whereas no notable difference in porosity was observed between SHT and as-built parts. There was no evidence of any recrystallization occurring following the post-fabrication treatments as elongated columnar grain structures observed within as-built part were found to be maintained even after SHT and HIP process alongside the strong (100) crystallographic texture. Emphasis was laid upon understanding the influence of SHT and HIP on mechanical properties through stress-strain curves and work-hardening behaviour. (C) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

This study delves into the impact of post-fabrication Solution Heat Treatment (SHT) and Hot Isostatic Pressing (HIP) on Hastelloy X parts, revealing that post-fabrication HIP treatment significantly reduces porosity content while SHT shows no noticeable difference compared to as-built parts. Furthermore, there is no evidence of recrystallization occurring after post-fabrication treatments, with the original columnar grain structure being preserved.