Influence of nickel on microstructure and mechanical properties of medium-manganese steels

Abstract

To combine the advantage of density reduction and excellent performance, nanometer-sized B2 particles were introduced into the δ ferrite matrix of high-aluminium low-density steel by the addition of nickel (Fe–0.2C–11Mn–6Al–4/8Ni). Compared to Fe–0.2C–11Mn–6Al (0Ni) steel, the hardness and tensile strength of 4Ni and 8Ni steels are significantly improved. The improvement of tensile strength in 4Ni and 8Ni steels was primarily contributed by the precipitation strengthening or solution strengthening of B2 particles in δ ferrite. At the higher annealing temperature, the original dislocation density in δ ferrite is lower. However, dislocation multiplication during tensile deformation was more significant in the sample annealed at higher temperature, which was responsible for a higher work hardening rate.

Molecular dynamics study on the effect of Ni atoms on the crack arrest performance of Fe–Ni alloy

“…[1][2][3] Among these elements, Ni is considered to be an effective option to improve the fracture toughness of low alloy high strength steel. [4][5][6][7] Based on current understanding, Ni exists in the form of solid solution in ferrite matrix in steel alloy, and does not form second phase particles, which indicates that the strength of steel can be improved by solid solution strengthening. [8,9] Adding Ni to iron-based powder metallurgy materials can promote the shrinkage of materials in the sintering process and improve the toughness of materials to a certain extent.…”

Special issue on ‘Medium manganese steels’

“…Cai et al [27] report the favourable effects of Ni ( ∼ 4-8 wt-%) in a high Al containing ( ∼ 6 wt-%) medium Mn steel on strength, RA content and strain hardening rate. These effects are found to depend on annealing temperature-dependent precipitation or dissolution of nanometric (20-80 nm) B2 particles in δ-ferrite and dislocation characteristics during deformation.…”