Hardness anomalies on Cr 1−x Fe x (0.05<x<0.323) alloys: Mössbauer effect study

The hardness of Cr_1-xFe_x α solid solutions presents an anomalous behaviour in the range 0.10<xFe<0.30, that has been explained either by magnetic or electronic effects. In order to verify wether the anomalies were intrinsic to that phase or were induced by impurities, measurements of microhardness and isomer shift of samples of high purity Cr_1-xFe_x α solid solutions (0.05<xFe<0.323) were carried out. We found that the hardness presents a maximum and a minimum for xFe-0.19 and xFe-0.17, respectively, which are inferior to the amplitudes of the anomalies found by previous authors using lower purity alloys. Within the limit of experimental error, the isomer shift at room temperature varies linearly with the composition. These results suggest that impurities play a major role in determining the magnitude of the hardness anomalies and that electron transfer varies smoothly in the concentration range studied.