The effect of different HIP treatments on the microstructure and material properties of PBF Ti-6Al-4V

Hot Isostatic Pressing (HIP) is today an important post process for metal additive manufacturing since HIP:ing will eliminate the internal defects such as porosity, cracks and voids that is formed in the material during the printing process.

The thermal post processing like Hot Isostatic Pressing (HIP) and heat treatment will affect the microstructure, grain morphology, internal defects and in the end the static and dynamic material properties of PBF Ti-6Al-4V. The HIP and heat treatment process for PBF Ti-6Al-4V have been under investigation the last few years but it has not yet been concluded what is the best overall thermal post processing for this material. There are several different approaches on how to HIP PBF Ti-6Al-4V for optimum results including sub-Beta, near-Beta and super-Beta transus treatments with and without rapid quenching in the end of the HIP cycle. This presentation summarizes the findings from several studies on PBF Ti-6Al-4V where the microstructure, mechanical proprieties and fatigue properties have been evaluated for different HIP treatments mentioned above. It is found that a low sub-Beta transus HIP temperature gives improved static properties compared to the conventional near-Beta tarsus HIP treatment, a super-Beta transus HIP treatments can break up the columnar grain structure and that all HIP treatments give improvement in fatigue performance.