Evaluation of pore re-opening after HIP in LPBF Ti–6Al–4V

Abstract

Higher build rates in Laser Powder Bed Fusion (LPBF) process in combination with Hot Isostatic Pressing (HIP) have been proposed to reduce the cost-per-part of additive manufacturing. However, inert gas trapped in the pores could cause healed pores to re-grow after elevated temperature exposure. Therefore, understanding the possible effects of this pore re-opening phenomenon is crucial in maintaining quality of parts subjected to elevated temperatures during service. The aim of the present study was to investigate pore re-opening after HIP in Ti–6Al–4V parts by exposing samples to different elevated temperatures for varying times. The changes in the pore content were studied using microscopy and micro X-ray computed tomography in combination with gas content analysis. Based on the results, it was concluded that for typical service temperatures of Ti–6Al–4V, pore re-opening was minimal.