On the effect of austenite stability on high cycle fatigue of TRIP 700 steel

The high cycle fatigue behavior and the role of austenite stability on fatigue performance of low-alloy TRIP steel 700 have been experimentally investigated. The material was subjected to heat treatment in order to produce microstructures with different initial retained austenite volume fraction and austenite stability. High cycle fatigue tests were carried out to determine the S–N fatigue curve while austenite stability was measured by implementing a special technique for determination of M s σ temperature. The effect of austenite stability on fatigue behavior was assessed by measurements of volume fraction austenite before and after fatigue testing. The fatigue results indicated that austenite stability influences fatigue performance of TRIP steel in the high cycle regime, especially at high cyclic stresses.