Synthesis, microstructural and phase evolution in Ti-2Ni and Ti-10Ni binary alloys consolidated by spark plasma sintering technique

The availability of lower-cost titanium with unique properties required for engineering applications such as in automobile, aerospace and biomedical has created a renewed interest in titanium and its alloys. However, poor sinterability due to high affinity of titanium for oxygen results in the production of less dense sintered product. While this may be of benefits in biomedical applications, it is deleterious to engineering applications such as in aviation parts that require high fatigue performance. In order to overcome this challenge, this study synthesized and consolidated Ti-2Ni and Ti-10Ni binary alloys using spark plasma sintering technique. Ti (Gd 1) and Ni elemental powders were mixed together in a TF2 Turbula mixer, at the speed of 101 rpm for 8 h. Sintering was conducted at 850, 1100 and 1200 degrees C under vacuum using the spark plasma sintering system. The applied pressure, heating rate and holding time were maintained at 50 MPa, 100 degrees C/min and 10 min respectively. Sample characterization was carried out with the aid of X-ray diffractometer and scanning electron microscope, equipped with energy-dispersive X-ray spectroscopy. The density and hardness of the sintered alloys were obtained using the Archimedes technique and Vickers microhardness tester respectively. The results showed that the relative density and hardness increased with increasing sintering temperature for the sintered Ti-2Ni and Ti-10Ni alloys. Generally, it was observed that increasing the sintering temperature and nickel addition improved the sinterability and densification of the sintered alloy.