Deformation of Single Crystalline Mn3Sn

Abstract

AbstractSingle crystalline Mn3Sn was chosen as a model material for a study of the deformation machanism of DO19 ordered alloys. Single crystals were grown by the Bridgman method in an argon atmosphere. Compression test specimens of six different orientations were cut from the bulk single crystals by electric discharge machining and polished for slip trace analysis. Compression tests were carried out in an Instron testing machine at a strain rate of 1.2 X 10−3 s−1 at temperatures ranging from 77 OK to 1180 oK. Tests at temperatures above 400 oK were performed in an argon atmosphere while those of lower temperatures were performed in air.Preliminary results were obtained and analyzed in order to determine the temperature and orientation dependence of the operating slip systems and the yield stress. Basal slip was observed to be the dominant slip mechanism. Slip lines were observed on specimen surfaces compressed at low temperatures but such observations were difficult on specimens deformed at temperatures above 1000 OK due to surface contamination.An anomalous positive temperature dependence of the critical resolved shear stress for basal slip was found, similar to that reported for octahedral slip in many intermetallic compounds with the Ll2 structure.