Produ ction and characterization of porous TiNi shape memory alloys

In the present study, porous TiNi alloys (Ti-50.6 at. %Ni) with porosities in the range of 21%-26% were prepared, applying the conventional powder metallurgy fabrication route in which magnesium was used as the getter, resulting in a single austenite phase dictated by the composition of the starting prealloyed powders and entirely free from secondary brittle intermetallics, oxides, nitrides, and carbonitrides. Although porous TiNi alloys produced by conventional sintering have not been found to be appropriate for bone replacement applications involving bone ingrowth due to their small pore size (4-65 μm on average, depending on compaction pressure) and low porosity, they are appropriate for filtering applications due to their highly interconnected pore structures (over 90%), which provide excellent permeability. Since they meet the main mechanical requirements expected from an implant material, such as low Young’s moduli, high strength, and ductility, they can also be used in the processing of metallic foams with gradient porosity.