FABRICATION OF Ti-Ni SHAPE MEMORY ALLOY BY METAL INJECTION MOLDING

摘要

We tried to fabricate Ti-Ni shape memory alloy using elemental Ti and Ni powders by metal injection molding. Gas-atomized Ti powder, TiH_2 powder and carbonyl Ni powder were used in this study. The fabrication conditions, such as debinding and sintering conditions, of Ti-Ni alloy were investigated experimentally. The density of the shape memory treated compacts of Ti and TiH_2 powders were approximately 78% and 87%, respectively. Thus the use of fine TiH_2 powder resulted in improvement of sinterability of this alloy. The peaks of the reverse and martensitic transformation temperatures of the compacts were approximately 40 K lower than those of the wrought alloy. The tensile strength and elongation of the as-sintered compacts of TiH_2 powder were more than 200 MPa and 3%, respectively. The deformation resistance of the compacts of Ti powder was fairly lower than that of the compacts of TiH_2 powder. The shape memory treatment resulted greatly in improvement of shape memory characteristics of the as-sintered compact.