ÇİFT FAZLI ÇELİKLERDE MARTENZİT MORFOLOJİSİNİN STATİK DEFORMASYON YAŞLANMA DAVRANIŞI ÜZERİNE ETKİSİ.

In this study, strain ageing behaviour of dual phase steel with different martensite morphology was investigated. Three different types (Intercritical annealing, intermediate quenching and step quenching) of heat treatment was applied in the critical temperature (775 °C). Ageing experiments after 4 % prestrain were carried out at 180 °C for different times ranging from 10 to 160 min. The microstructure after different heat treatments applied to the work pieces with the network, fiber, and the bulky martesite morphologies have been identified. It was found that the martensite morphology has no effect on the trend of ΔY (an increase in strength due to strain ageing), YS and UTS at different ageing times for 180 °C. However, at a given ageing time for 180 °C ΔY, YS, UTS and hardness values of fibrous martensite are higher than network or bulky martensite. [ABSTRACT FROM AUTHOR]