Strengthening mechanisms of P/M extruded titanium materials with additive hydrogen

Abstract

TiH2 raw powders were directly consolidated by cold pressing, sintering and hot extrusion to fabricate pure Ti materials. The residual hydrogen content depended on the sintering temperature, and showed a significant effect on α/β phase transformation during hot extrusion. When 0.33 mass% hydrogen was contained in the sintered compact, α→β phase transformation occurred completely at extrusion temperature of 1073 K, and resulted in the formation of <000>α texture of the extruded Ti material. This texture was completely different from that of the conventional extruded Ti materials (<10-10>α texture) with very few contents of hydrogen. The former indicated extremely high tensile strength (σ) of 959 MPa and enough elongation (δ) of 27.6 % compared to P/M extruded pure Ti materials with σ= 634 MPa and δ= 29.9 %.