HIGH VELOCITY COMPACTION AND CHARACTERISTICS OF Ti POWDER

High velocity compaction (HVC) is a recently developed technology for forming high density metallic parts with high efficiency, whose densification is realized through the strong, impact wave generated by liquid-pressure controlled by heavy hamper. This technology is thought to have an excellent balance between properties and cost and has several advantages over other existing forming technologies including high and homogeneous green density, low cost, low springback and high precision It is extremely competitive to prepare powder metallurgy parts with high density, high strength, high precision and low cost With a high hardening rate, Ti powder is difficult to be formed through traditional pressing methods, although advanced forming methods are effective for increasing Its density: Such as hot-pressing and isothermal-statistic pressing, they are very expensive. HVC would thus be highly attractive to solve these problems of low density and high cost ill forming Ti powder. In this paper, the process of HVC forming Ti powder was studied. Two kinds of samples, the rings with 60 mm outer and 30 mm inner diameters and the cylindricals with 20 mm diameter were prepared through HVC, respectively. The influences of impact energy and filling weight on the green density were investigated. The results show that, for the ring samples, the maximum of green density is 4.00 g/cm(3) and its relative density is 88.9% at an impact energy of 3.804 kJ. However, for the cylindrical samples, the maximum of green density of 4.38 g/cm(3) and its relative density is 97.4% at and impact energy of 1.217 kJ. For the both kinds of samples, the green density increases with increasing impact energy while decreases with increasing filling weight. Impact energy per weight is helpful to characterize the green density obtained at different dimension, impact energy and filling weight.