Fabrication of TiNi Shape Memory Alloy by Spark-Plasma Sintering and Its Thermo-Mechanical Properties

Ti-Ni shape memory alloy was fabricated by spark-plasma sintering method, and isothermal tensile and recovery stress tests were carried out on the alloy. The effect of fabrication conditions, such as sintering and heat-treatment conditions, on the mechanical properties of the alloy were investigated. The appropriate sintering and heat-treatment conditions were found out by measuring the density, observing the microstructure and analyzing the X-ray diffraction of the sintered compacts. The relative density of the sintered compacts was around 98%. The obtained alloy showed apparent shape memory effect, but its tensile strength and elongation were much less than those of cast material of the same alloy. The recovery stresses for various stress-strain histories by a temperature rise from 293 K to 353 K were around 230 MPa.