Wear Behavior of Hot Forged NiTi Parts Produced by PM Technique

Abstract

Pre-alloyed NiTi powders were pressed at 400 °C, sintered at 1250 °C for 2 h and then cooled down at the rate of 5 °C/min to room temperature inside oxygen-free furnace. Later these sintered parts were forged at ~ 1050 °C [(± 25 °C) (Forged.1: 15% and Forged.2: 30%)]. Wear behaviors of the un-forged and hot forged parts were investigated. Wear tests were carried out via a pin-on-disk wear testing device according to ASTM G132-96 standard. The wear tests were performed for various sliding distances (200 m, 400 m and 600 m) at the speed of 1.2 m/s and under different loads of 5 N, 10 N and 15 N. Vickers macro-hardness values were measured at HV2. The samples were analyzed via SEM, EDS and MAP to determine the microstructure. Wear losses, wear rates and friction coefficients were measured in detail. The results showed that the best values in terms of wear and friction coefficient were obtained for 30% hot forged sample which had a hardness value of 612 HV and a density of 5.94 g/cm3. © 2019, The Indian Institute of Metals - IIM.