Self-healing effect on worn surface of NiTi shape memory alloy

The effect of shape memory on the wear track recovery of a NiTi alloy after sliding tests at various temperatures was investigated. The surface profiles of the wear track were obtained before and after heating the worn samples to a temperature above its austenitic transformation finish temperature. The results showed that similar to 28% of wear track area was recovered at 0 degrees C wear testing temperature under a normal load of 80 N due to martensite-austenite transformation upon heating. The recovery reached to a value of similar to 7% at a wear testing temperature of 25 degrees C. The shape memory effect of the material was also characterised by three point bending tests at various testing temperatures. Comparison of shape memory effect in wear and bending tests showed that with increasing testing temperature, the amount of per cent recovery decreased and followed almost the same trend in both tests.