Comparative Study on Cold Compaction Behavior of TiH2 Powder and HDH-Ti Powder

The compaction mechanism of titanium hydride powder is an important issue because it has a direct impact on density and strength of green compacts and ultimately on the physical and mechanical properties of a final sintered products. In this paper, the characteristics and compaction behavior of titanium hydride and hydrogenation-dehydrogenation titanium powders are comparatively studied and analyzed for better understanding of compaction mechanism of brittle low-strength titanium hydride. The results indicate that the particles of titanium hydride powder are easily crushed under compaction loading at relatively low pressure well below compression strength of bulk titanium hydride, the degree of particle crushed increases with the increase of pressure. The compaction behavior of titanium hydride powder mainly includes the rearrangement and crushing of particles in the early compaction stage, minor plastic deformation, if any, and further rearrangement of particle fragments with filling the pores in the later stage. Such compaction behavior provides relative density of green hydride compacts higher than that for titanium powder of the same size. The relatively coarse titanium hydride powder with wide particle size distribution is easier to fill the pores providing highest green density.

Investigation of the Pore Morphology of the Hydroxyapatite-Based Bicomposites Processed by Two Step Sintering

Porous hydroxyapatite (HAp) based biocomposites used in biomedical applications were developed in this paper as artificial bone substitute for vertebrae grafts. The trabecular or spongy bone tissue is an open-cell porous network having 40-90% porosity. In order to obtain a porous structure calcium carbonate and ammonium bicarbonate were added as foaming agents to the biocomposite matrix. The biocomposite matrix was prepared using submicronic powder particles of HAp and titanium hydride powder, which was added as reinforcement’s precursor as well as foaming agent. The aim of this study is to emphasize the effect of the foaming agent additions on the pores morphology by performing analyses at both macro and micro scale. These analyses consist of linear measurements, surface auto-detection and statistics of the pores and optical images as well. The powders mixture was homogenized in a planetary ball mill, uniaxial cold compacted and then heated in argon atmosphere using the two step sintering technique.

Study about the Influence of Two-Steps Sintering (TTS) Route for an Alloy Based on Titanium

This paper describes the influence of two-steps sintering regime temperatures concerning the final properties of titanium hydride based alloy obtaining by Two-Steps Sintering (TTS) route, which is a method that is part of the Powder Metallurgy (PM) technology. The initial titanium hydride powder has been mixed with some metallic powders as: Alumix, Mn, Zr, Sn and graphite was added in different proportions for improving the final mechanical properties. The Two-Steps Sintering (TTS) route have been applied for obtaining a low-cost Ti- alloy. The effect of the sintering regime temperatures on the height and diameter shrinkages and density for these alloys based on titanium hydride powder was studied