Structures and Properties of Near-Rapidly Solidified Fe-12Mn-9Al-1.2C Dual-Phase Lightweight Steel Containing 3 wt Ni

摘要

Fe-Mn-Al-C lightweight steel possesses not only excellent comprehensive mechanical properties, but also a low density, which is attractive to the automotive industry. In the present paper, an austenite stabilizer Ni element which usually increases the austenite content was added and its effects on the structure and mechanical properties of a near-rapidly solidified Fe-12Mn-9Al-1.2C dual-phase lightweight steel strip were studied. It was found that the addition of 3% Ni did not show the potential to increase the austenite content or enhance the mechanical properties of Fe-12Mn-9Al-1.2C dual-phase lightweight steel strip. Moreover, the addition of 3% Ni deteriorated the thermal stability of Fe-12Mn-9Al-1.2C steel. In the strip with the addition of Ni, the formed metastable austenite almost fully transformed into ferrite + κ-carbide at a lower annealing temperature. The formation process of constituent phase in this near-rapidly solidified dual-phase lightweight steel was analyzed. The related results suggested that the constituent phases of the near-rapidly solidified dual-phase lightweight steel depended on the liquid/solid transition, which was controlled by both thermodynamics and kinetics factors.