Formation of strain-induced martensite in austempered ductile iron

摘要: The present work has been taken up to study the influence of microstructure on formation martensite in austempered ductile iron. Ductile iron containing 1.5 wt.% nickel and 0.3 molybdenum was subjected two types austempering treatments. In first, called as conventional austempering, samples were for 2 h at 300, 350 or 400 °C. second treatment, stepped initially 300 °C 10, 20, 30, 45 60 min. These subsequently Tensile tests revealed considerable variation strain-hardening behaviour with different heat case it found that exponent increased increasing temperature. strain hardening observed short periods first step austempering. Study microstructures associated strain-induced martensite. There a greater propensity more blocky austenite. Retained austenite form fine films between sheaths ferrite relatively stable. Studies morphology, size carbon content retained important parameters controlling their tendency transform