Effect of austenite stability on the hole expansion behavior of δ-TRIP steels

• Published in: Materials today communications Vol. 24; p. 101034
• Main Authors: Xu, X., Xu, B.Y., Chen, P., Liu, R.D., Wang, G.D., Yi, H.L.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-09-2020
• Subjects: Hole expansion property; Isothermal bainitic transformation; Retained austenite; Stability; δ-TRIP steel; Isothermal bainitic transformation; Retained austenite; Stability; Hole expansion property; δ-TRIP steel
• ISSN: 2352-4928; 2352-4928
• DOI: 10.1016/j.mtcomm.2020.101034

This paper deals with the assessment of the stability of retained austenite in δ-TRIP steels at two different isothermal holding time durations. Longer holding time leads to an improvement in austenite stability by greater carbon enrichment. This caused a significant increase in the hole expansion ratio at a tensile strength of 800 MPa. The microstructure mediated approach was employed to characterize the difference arising from different holding durations. The deformation-induced transformation of austenite into martensite mapped on the specimens after hole expansion proved that the austenite stability plays a significant role in the hole expandability of δ-TRIP steels.