Aging Behavior of Intercritically Quenched Ductile Iron

Although extensive aging and strain (bake hardening, BH) studies have been carried out on dual-phase steels, the behavior of dual matrix structure (DMS) ductile iron (DI), as a potential way to improve its mechanical properties, has not addressed until now. This research was designed study DI with ferrite-martensite structure. DMS-DI martensite volume fraction 30% produced by intercritical austenitizing at 785 °C followed quenching in water room temperature. Aging treatments were without pre-straining temperatures 140, 170, 220 for 2–10,000 min. investigated light optical microscopy (LOM) unaged samples scanning electron (SEM) selected after treatments. The effect conditions properties investigated. Microhardness measurements ferrite also examined function conditions. increase yield strength due determined. results indicate that small ultimate tensile UTS. It is shown increased maximum value 45 MPa (~11% increase) particular time, which found be dependent peak response decrease strength, observed attributed tempering confirmed microhardness measurements.