Preparation of Ni2MnGa shape memory alloys (SMA) by Spark Plasma Sintering (SPS) and property comparisons of sintered alloys to arc-melted alloys are investigated. The Ni2MnGa alloy with relative density of 99.6% is obtained with a maximum pressure of 80 MPa and a maximum temperature of 1173 K applied in the sintering process. Heat treatment is subsequently performed at 1073 K for 864 ks in vacuum and slowly cooled. The martensitic transformation temperatures, Ms, Mf, As, Af, are determined as 235 K, 220 K, 239 K and 254 K respectively. The elastic moduli and Poisson ratio are 107.9 GPa and 0.38 respectively. Tensile and compression tests are conducted at room temperature. The tensile fracture strength is increased in sintered alloys. For compression tests, sintered alloys show compressive ductility of 14.2% with transgranular cracking while arc-melted alloys only have 1.5% plastic deformation and both intergranular cracking and transgranular cracking. Furthermore, the sintered alloys possess higher yield stresses and fracture strengths.
|Number of pages||4|
|Journal||Materials Science Forum|
|Publication status||Published - 2000|
|Event||Proceedings of the 1999 International Symposium and Exhibition on Shape Memory Materials (SMM'99) - Kanazawa, Jpn|
Duration: 1999 May 19 → 1999 May 21