"Squeezed" pores in additively manufactured titanium: imaging of their morphology and opening process upon heat treatment

Different forms of porosity can occur in the laser powder bed fusion (L-PBF) process, hence the hot isostatic pressing method (HIP) is becoming a routine postprocessing method for critical applications: this closes the pores and improves the microstructure through high temperature and simultaneous high pressure. However, despite performance improvements that are well proven, some pores may open up on subsequent heat treatment, indicating that these pores have been “squeezed” and not fully closed. This work focusses on imaging these HIPed “squeezed” pores in different static samples at high resolution, artificially induced and characterized prior to HIP by lab CT. In situ heat treatment using a furnace at beamline ID19 in combination with rapid μCT scans will allow visualization of the opening of these pores in near real time. The gained knowledge is important for an improved understanding of the porosity in L-PBF material and about which pores are more critical.