1988 Volume 29 Issue 10 Pages 781-789
The effects of hydrostatic pressure on the martensitic transformations from β1 to β1′ in single- and poly-crystals of a Cu-28.8Al-3.8Ni (at%) alloy, and from β1 to γ1′ in single crystals of a Cu-28.6Al-3.2Ni (at%) alloy have been investigated by means of electrical resistivity measurements and in-situ optical microscope observations under hydrostatic pressures up to 7 GPa. The results obtained were as follows: Transformation temperatures under hydrostatic pressure increased linearly with pressure, and the pressure dependence of thermodynamic equilibrium temperature obtained from the measured transformation temperatures was about 5 K/GPa for both alloys irrespective of the single- or poly-crystals. In-situ optical microscope observation revealed that the morphology and growth and/or shrink behavior of hydrostatic pressure-induced martensites were identical to those of the thermally induced ones. A thermodynamic analysis showed that the effects of hydrostatic pressure on martensitic transformations were successfully explained by taking account of the volume change associated with the martensitic transformation.