Large thermal hysteresis NiTi Belleville washer fabricated by metal injection moulding

In this work, Ni(49.4)Ti(50.6)Belleville washers are prepared by metal injection moulding (MIM). The martensitic transition temperatures and service performance of washers were investigated. The thermal hysteresis has reached 63.1-71.6 degrees C, which is much higher than documented data in binary NiTi alloys. Ti2Ni and Ni(4)Ti(3)phase are observed in XRD patterns, which is responsible for the large thermal hysteresis. In the service tests, the restoring forces are higher than 40 kN, which are sufficient to ensure a tight connection of the fasteners. The loop resistance and high-current test have proved the safety of MIM NiTi Belleville washers compared to traditional steel spring washers, which can meet the challenge in complex outdoor circumstances.