Nanoindentation investigation on the initiation of yield point phenomenon in a medium Mn steel

• DOI: 10.1016/j.scriptamat.2018.03.015
• Publication Date: 2018-03-20T13:01:46Z
• Authors: B.B. He; Z.Y. Liang; M.X. Huang
• Keywords: Dual-phase steel; Beta ferrite

Abstract In general, the medium Mn steel with a dual phase microstructure of austenite and ferrite has a yield point phenomenon. It is still not clear which phase firstly initiates the plasticity and therefore governs the yield point phenomenon. In this paper, the mechanical behaviours of ferrite and austenite phases are investigated by nanoindentation. It is found that the large ferrite grains in which dislocations are present have a lower resistance to dislocation plasticity as compared to the austenite phase and the small ferrite grains, suggesting that the large ferrite grains shall be responsible for the initiation of yield point phenomenon.