Evolution of microstructure with increasing carbon content and its effect on mechanical properties of disordered iron–aluminium alloy

Correlation of microstructure and mechanical properties of hot-rolled Fe–7 wt.% Al with varying carbon contents has been investigated in detail. The microstructures of the alloys change significantly with an increase in the carbon content. An alloy with 0.012 wt.% carbon shows a single ferrite phase, whereas with increase in carbon up to 0.65 wt.%, the microstructure evolves into a dual phase consisting of ferrite and $$\upkappa $$ -pearlite. At about 1.5 wt.% carbon, the alloy exhibits only $$\upkappa $$ -pearlite and with a further increase in carbon to 2.2 wt.%, an additional phase starts precipitating in the form of graphite. The room temperature tensile strength of the alloy increased significantly with an increase in the carbon content, which is in agreement with the microstructure. The yield strength and hardness of the steels with different carbon contents can be correlated well with the inter-barrier spacing in different steels.