The relation of short-range order to the deformation behaviour of copper-rich copper-aluminium alloys

Abstract

The relation of short-range order to the deformation behaviour of copper-aluminium alloys containing nominally 6, 11 and 15 at. % aluminium was investigated by x-ray diffraction, resistivity measurements and tensile tests. X-ray diffraction was used to investigate the short-range order in these alloys. Resistivity changes served as a measure of changes in the short-range order resulting from different heat treatments. The deformation behaviour of single crystal specimens was investigated by means of tensile tests. The yield drop of quenched single crystals showed a high degree of correlation with the short-range order; a reduction in the order before deformation was associated with a reduction in the yield drop. Changes in the short-range order had no measurable effect on the deformation behaviour beyond the yield drop. The stress required to reduce the short-range order by slip (Fisher stress) appears to be closely associated with the dislocation pinning resulting from short-range order.