Tensile anisotropy in Cu-Ni-Mn-Sn-Al alloys

Abstract

In the present study, the tensile anisotropy of age-hardened Cu-6Ni-2Mn-2Sn-2Al, Cu-6Ni-2Mn-2Sn-2Al, and Cu-6Ni-2Mn-5Al alloy sheets, either perpendicular or parallel to the rolling direction, was examined. It was found that age-hardened Cu-Ni-Mn-Sn-Al alloys have higher tensile strength along the T orientation than L orientation at high rolling ratios. Such a trend was most notable in the high Al containing Cu-6Ni-2Mn-5Al alloy among the alloys studied. At high rolling ratios, well-developed deformation bandlike structures were observed to be mostly aligned perpendicular to the rolling direction for each alloy. These deformation bandlike structures appeared to be responsible for the higher tensile strength along the T orientation. The transmission electron microscopy (TEM) examination demonstrated that the deformation bandlike structures consisted of tangled dislocation networks, which were further thickened with the addition of Al or the reduction of Sn. The stacking fault energy (SFE) of Al and Sn, as related to the ease of cross-slip, is believed to be responsible for the present observation.