Effect of Morphology of Titanium Carbide on the Ductility of Fe-30 mass%Cr Alloys

Effects of morphology of titanium carbides on the ductility of Fe-30 mass%Cr alloys containing carbon and titanium were investigated by tensile test at low temperatures. Carbon and titanium contents vary from 0.011 to 0.071 mass%, and from 0.094 to 0.60 mass%, restectively. Ti/C ratio is about nine times. Three kinds of processes including heat treatments with or without solution treatment and cold rolling were adopted to obtain different types of morphology of fine grain boundary titanium carbides (0.05 μm), fine spheroidal titanium carbides (0.05 μm) within the grains, and coarse globular titanium carbides (0.5 μm) within the grains. Ductility was evaluated by transition temperatures in reduction of area.The results obtained are summarized as follows:(1) Transition temperatures of the specimens containing grain boundary titanium carbides are remarkably higher than those of the specimens containing titanium carbides within the grains.(2) Transition temperatures of the specimens containing fine spheroidal titanium carbides within the grains are lower than those of the specimens containing coarse globular titanium carbides.(3) Transition temperatures of the specimens containing spheroidal titanium carbides (≤0.5 μm) within the grains do not increase with increasing the volume fraction of titanium carbides.