Microstructure and mechanical properties of Fe–7Al based lightweight steel containing carbon

Abstract

The effect of carbon on the microstructure and mechanical properties of lightweight steel based on Fe–7 wt-Al produced by air induction melting with flux cover is investigated. The ingots were hot worked to plates and were characterised. Steel containing 0.02 wt-C exhibited a single phase microstructure Fe–Al(α), whereas steel containing 0.5 and 1.0 wt- carbon exhibited a two-phase microstructure containing significant amounts of Fe₃AlC_0.5 precipitates in Fe–Al(α) matrix. Microhardness of the matrix decreases with increasing carbon content due to depletion of aluminium from the matrix to form Fe₃AlC_0.5 carbides. The bulk hardness, room temperature strength increases and tensile elongation decreases with increasing carbon content. However, at 873 K the improvement in strength as well as creep properties with increasing carbon content is marginal.

Keywords

Lightweight steel Air induction melting Iron aluminium alloys Tensile properties Creep properties Mechanical properties

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