THE WEAR AND FATIGUE CHARACTERISTICS OF FE-MN-SI SMA

摘要

The friction and wear characteristics of Fe-17Mn-5Si-10Cr-5Ni shape memory alloy have been studied by the means of wear experiments, XRD,SEM observation in dry and oily friction, and compared with high-Mn steel. The results show that, in dry friction there is not ε martensite in the surface of SMA alloy with bad wearing resistance, worse than that of high-Mn steel and its friction mechanism is adhesive wear; in oily friction there exists much ε martensite in the surface with good wearing resistance, much better than that of high-Mn steel and its friction mechanism is abrasive wear. The good wearing resistance of Fe-17Mn-5Si-10Cr-5Ni shape memory alloy in oily friction mainly attributes to stress-induced γ→ε martensitic transformation during the friction. The experimental results show that the strain fatigue life of Fe-17Mn-5Si-10Cr-5Ni alloy with a strain amplitude of±1.5% is about 10 times more than that of the ecumenic engineering materials. Some automobile transmission idlers have separately made of this material and 1Cr18Ni9Ti austenite stainless steel, and have been tested. The results prove that, the fatigue life of the former is 11 times longer than that of the latter.