Mechanical Properties and Tensile Fracture Mechanisms of Fe–Mn–(Al, Si) TRIP/TWIP Steels with Different Ferrite Volume Fractions1. Issue 11 (1st June 2015)

• Record Type: Journal Article
• Authors: Dong, Fu Yuan; Pang, Jian Chao; Zhang, Peng; Duan, Qi Qiang; Zhang, Zhe Feng
• Is Part Of: Advanced engineering materials. Volume 17:Issue 11(2015:Nov.)
• Page Start: 1675
• Page End: 1682
• Publication Date: 2015-06-01
• Subjects: Materials -- Periodicals; 620.11
• DOI: 10.1002/adem.201500108
• Languages: English
• ISSNs: 1438-1656

Abstract

Abstract : The mechanical properties, damage, and fracture behaviors of Fe–Mn–(Al, Si) steels containing different Mn content and volume fraction of ferrite have been investigated through tensile testing. It is found that the volume fraction of ferrite has significant influences on the mechanical properties and damage accumulation. With increasing the Mn content, both the yield strength and ultimate tensile strength are decreased, while the uniform elongation is continuously increased, showing a typical trade‐off relation between strength and elongation. The difference in the work‐hardening behavior can be attributed to the increase in the stacking fault energy (SFE) caused by the addition of Mn. The failure mechanisms of the steels are found to be mainly influenced by deformation localization due to microstructural inhomogeneity. On the one hand, the Fe–Mn–(Al, Si) steel with a much more uniform distribution of austenite shows a slower rate of damage growth and a continuous void nucleation during the deformation process, resulting in a higher void density prior to the final fracture. On the other hand, the Fe–Mn–(Al, Si) steel with more ferrite exhibits accelerated void growth and catastrophic coalescence. Abstract : The mechanical properties and fracture behaviors of four Fe–Mn–(Al, Si) TRIP/TWIP steels with different ferrite volume fractions are investigated. Three fracture modes exist for the steels due to the variation of the fracture stress and the macroscopic instability stress: fully normal fracture for Fe–15Mn–Al–Si steel (hard ferrite matrix and austenite second phase); necking + normal fracture for Fe–20Mn–Al–Si steel (ductile austenite matrix and ferrite second phase); and necking + shear fracture for Fe–(25, 30)Mn–Al–Si steel (fully austenite phase).