Abstract
In this study, the metal injection molding process for high performance Ti compacts were investigated. Low oxygen gas atomized Ti powder was used for starting powder. As a result of using Mo vessel and sponge Ti, sintered Ti compact at 1523 K showed the excellent mechanical properties (tensile strength: 522 MPa, elongation: 21%), which was similar to JIS 3 grade of wrought Ti. This was due to the protection of oxidization. By blending with Hydride dehydrozation powder (high oxygen content) and gas atomized powder, tensile strength was improved significantly without large loss of the ductility (600 MPa, 13%). This seemed to be due to the high oxygen contents and more uniform oxygen distributions (solid solution strengthening). By MIM in-process nitriding combined with sintering appropriately, the surface hardness of Ti compacts increased dramatically and it decreased continuously to the inside.
