Fabrication of Porous NiTi Shape Memory Alloy by Elemental Powder Sintering

Porous equi-atomic NiTi Shape Memory Samples were fabricated using the Elemental Powder Sintering technique for varying starting powder sizes of Ni and Ti. The porosity was primarily dependent on the starting powder sizes, and less dependent on the sintering parameters and compaction loads. Sintering at higher temperatures of 1120°C and 48 hrs resulted in a completion of reaction to equilibrium NiTi. The average pore size was found to be in proportion to the starting powder size. The martensitic-austenitic transformations as determined from the electrical measurements had a broad transformation behavior. Compressive tests performed on the sample showed a recoverable strain of up to 2.5 %.