Effect of Heat Treatment on the Erosive Properties of NiTi Shape Memory Alloys

Slurry erosive properties of four NiTi alloys which are heat treated in different programs and 1Cr18Ni9Ti stainless steel have been systematically studied using a specially designed slurry-pot equipment. The erosive loss of five samples increase with the erosion time, velocity, mass ratio of sand to water and sand size. Four NiTi alloys exhibited very little difference in wear-resistance and they exhibited better wear-resistance than 1Cr18Ni9Ti stainless steel. NiTi-3 and NiTi-1 exhibited a little better erosive resistance than the others. The superelasticity and the superplasticity, not the hardness, are the key elements for the good anti-erosive properties of NiTi alloys. The heat treatments decrease the superelasticity but increase the plasticity greatly. Deformation occurred in the middle part of the NiTi-wire, and micro-cutting in the sides, which indicated that all the samples exhibit ductile material characteristics in the erosion.