期刊名称：Chemical Industry and Chemical Engineering Quarterly
印刷版ISSN：1451-9372
出版年度：2022
卷号：28
期号：2
页码：161-167
DOI：10.2298/CICEQ201222027J
语种：English
出版社：Association of the Chemical Engineers
摘要：Dual-phase ADI material microstructure consists of different amounts and morphologies of ausferrite and free ferrite, obtained by subjecting ductile iron to specific heat treatment. Its strength is lower compared to comparable ADI materials but exhibits a higher ductility, the major disadvantage of ADI. In the current study, an unalloyed ductile iron was intercritical austenitized in two-phase regions (α+Ƴ) at four temperatures from 840 to 780 °C for 2 h and austempered at 400 °C for 1 h to obtain dual-phase ADI with different percentages of free ferrite and ausferrite. Light and scanning electron microscopy was performed for the metallographic and fracture studies, respectively. Microscopy results were correlated to tensile testing results. The results indicated that, as the amount of ausferrite present in the matrix increases, higher values of strength and lower ductility are obtained. The fracture surfaces of dual-phase ADI microstructures with 22.8% of ausferrite in their matrix have regions of quasi-cleavage fracture around last-to-freeze zones, related to the presence of ausferrite in those areas. The specimens with the highest values of ausferrite of 86.8% among the dual-phase microstructure have a dominant quasi-cleavage type of fracture.
