Superplastic bulging properties of TA32 titanium alloy sheet under different strain paths were studied by carrying out high temperature gas bulging experiments. Four kind of elliptical dies with different minor-major axis ratios were used to achieve different biaxial tensile strain paths
and the rolling direction and transverse direction of the specimen were parallel to the major-axis direction of the die to analyze the deformation anisotropy. Based on the Barlat' 89 yield criterion under the non-associated flow criterion as well as the strain components
thicknesses and radius of curvature at the apex of the bulging specimens
the equivalent stress–strain curves under different strain paths were determined. The results show that the superplastic bulging properties of TA32 sheet have a remarkable strain path dependence
when the loading path changes from equi-biaxial tension to near plane strain
the ultimate bulging height of the sheet decreases
the thinning rate and peak stress increase
the elongation and formability decrease. Meanwhile
TA32 sheet exhibits significant anisotropy of mechanical properties under high-temperature biaxial tension. When the rolling direction is parallel to the first principal strain direction
the material has lower peak stress and higher plasticity