Investigation of physical, chemical, and technological properties of titanium powder obtained by thermal dehydrogenation in vacuum

Abstract

In recent times, there has been significant interest in powder metallurgy, driven primarily by the active development of additive manufacturing. Consequently, a pressing task is the development of methods for producing initial metal powders that are cost-effective while meeting high consumer standards. This research is a continuation of studies on titanium powders obtained through SHS hydrogenation and thermal dehydrogenation. The titanium hydride powders, previously obtained using SHS technology, were sieved, resulting in fractions that matched the granulometric composition of titanium powders of PTK, PTS, PTM, and PTOM grades. Subsequently, the titanium hydride powder samples underwent dehydrogenation through vacuum annealing in an electric resistance furnace. Throughout the dehydrogenation process, the kinetics of hydrogen release from the titanium powder were examined as a function of particle size. The macro- and microstructure, chemical composition, and technological properties of the dehydrogenated powders were thoroughly analyzed. It was determined that the titanium powder maintained its original polygonal fragmented shape after dehydrogenation. The average particle size decreased by 5–20 %, and “satellites” were observed on larger particles. Chemical analysis revealed that larger samples contained a higher level of residual hydrogen and gas impurities (Σ 0.77 wt. %) compared to finer powders (Σ 0.26 wt. %). Regarding the study of technological properties, the resulting powders exhibited the necessary characteristics for use in titanium powder metallurgy, with the exception of low flowability due to the particle shape and microstructural heterogeneity). In conclusion, this research has demonstrated the potential of the SHS hydrogenation and thermal dehydrogenation method in producing high-quality titanium powders.