Nb对Fe-28Mn-10Al-C低密度钢组织与机械性能的影响

开发制备了一种汽车用含0.5%Nb(质量分数)的Fe-28Mn-10Al-C-0.5Nb低密度钢,旨在研究Nb在奥氏体Fe-Mn-Al-C低密度钢中的存在形态,以及Nb添加对Fe-Mn-Al-C低密度钢组织与力学性能影响。结果表明,Fe-28Mn-10Al-C低密度钢中加入Nb后,奥氏体晶粒平均尺寸由39.49μm细化到13.67μm,且退火孪晶形成受到抑制。随着Nb添加,Fe-28Mn-10Al-C低密度钢的屈服强度和抗拉强度分别升高170MPa和64MPa,断后伸长率升高11.5%,强度与延展性表现出良好平衡。加Nb低密度钢的高强度与高韧性与Nb C析出相的沉淀强化和奥氏体细晶强化有关,且含Nb低密度钢屈服强度的升高主要由析出强化引起。

Effect of Nb on the Microstructure and Mechanical Properties of Fe-28Mn-10Al-C Low Density Steel

A novel Fe-28 Mn-10 Al-C-0.5 Nb low-density steel containing 0.5 wt%Nb for automobile was developed,aiming to study the effect of Nb addition on the structure and mechanical properties of austenitic Fe-Mn-Al-C low-density steel.With the addition of Nb,the average austenite grain size in Fe-28 Mn-10 Al-C low-density steel is refined from 39.49μm to 13.67μm,and the formation of twins is also suppressed.Besides,the yield strength and ultimate tensile strength of Fe-28 Mn-10 Al-C low-density steel increase by 171 and 64 MPa,respectively,and the elongation after fracture increases by 11.5%,revealing an excellent balance of strength and ductility.This is due to the precipitation strengthening of Nb C precipitates and fine grain strengthening of austenite.Precipitation strengthening plays an important role to increase the yield strength of Nb-added low-density steel.