Impact of in-situ dehydrogenation on densification kinetics in Ti-1Al-8V-5Fe alloy during spark plasma sintering

•High-density Ti185 alloy was fabricated by spark plasma sintering (SPS) method mainly from the low-cost TiH1.5 powder.•A modified creep densification model considering dehydrogenation effect was proposed for SPS-Ti185 alloy.•The dehydrogenation effect and residual hydrogen effect on densification mechanisms of SPS-Ti185 was discussed. Theoretically understanding the rapid densification mechanism of spark plasma sintering (SPS) is of great significance to the quality control of materials sintering but still limited. In this work, a modified densification creep model was proposed to elucidate the effect of hydrogen release on densification of Ti-1Al-8V-5Fe (Ti185) alloys during SPS. It is found that with the increase of hydrogen content, the effective stress increases by in situ dehydrogenation, but the hydrogen residual increases of activation energy (energy barrier), thus essentially it hinders dislocation mobility and matter transport then the densification is reduced.