Martensitic transformation in [110] single crystals of Cu-Al-Ni alloy

The martensitic transformations beta(1)(DO3)<->gamma(1)'(2H), beta(1)<->beta(1)'(18R(1)) and gamma(1)'<->beta(1)' were investigated in the [110] oriented single crystals of Cu-14.3A1-4.1Ni (wt.%) alloy. Thermal cycling and deformation tests in tension and compression were performed to induce the transformation process. The experimental results were summarized in a non-equilibrium sigma-T phase diagram (sigma-T map) which exhibits single-phase regions beta(1) and gamma(1)', two-phase regions beta(1)+gamma(1)' and beta(1)'+gamma(1)' and three-phase regions beta(1)+beta(1)'+gamma(1)'. The tensile and compression parts of the sigma-T map are not identical. This ''tension-compression asymmetry'' is compared with similar asymmetry observed for other crystal orientations.