Abstrakt

Effect of the chromium content on the room temperature hardness of binary cobalt-based, nickel-based and iron-based cast alloys

Patrice Berthod, Elodie Conrath

Many superalloys contain high quantities in chromium to resist hot oxidation and corrosion. Sometimes partly involved in carbides, the great majority of the Cr atoms are stocked in the matrix of the cobalt-based alloys, the iron-based ones, and some of the nickel-based alloys not too rich in aluminium. The presence of several tens percents of chromium in tha matrix may change its hardness. This work, carried out on binary MxCr alloys (M=Co, Ni or Fe; x varying between 0 and 33 wt.%), shows clear hardening effect of the chromium present in solid solution. For example the Vickers hardness of cobalt rises of one hundred points from 0 to 33 wt.%Cr. Similar effect exists for nickel while the dependence of the iron hardness on the chromium content is not monotonous.