shows the engineering and true stress-strain curves of the Cu-6.8Al alloy samples with different grain sizes. With a decrease in the grain size from 47m to 0.6m, the yield strength increases from 80 MPa to 450 MPa whereas the uniform elongation decreases from 82% to 28%. Even though, the elongation especially the uniform elongation is fairly large even when the grain size is as small as 0.6 m. In order to study the origin of the promising ductility, the strain hardening behavior of the samples with different grain sizes were compared and studied.