采用液压胀形试验分析了双向拉伸变形过程板材的应力梯度和应变分布 ,确定了双向拉伸变形状态下板材的应力应变关系曲线 ,探讨了不同应力状态下板材的本构关系。研究结果表明 ,不同应力状态下板材的本构方程存在一定的差异 ,双向拉伸变形条件更有利于发挥材料塑性变形的潜力。与单向拉伸相比 ,双向拉伸变形更有助于板料变形的均匀化 ,并抑制颈缩的产生和进一步扩展 The stress and strain distributions of biaxial tensile deformation plate were analyzed by hydraulic bulging test. The stress-strain curves of the plate under biaxial tensile deformation were determined, and the constitutive relations of the plate under different stress states were discussed. The results show that the constitutive equations of the plate under different stress states are different, and the biaxial tensile deformation conditions are more conducive to the plastic deformation potential. Compared with uniaxial stretching, biaxial stretching deformation is more conducive to the uniformity of sheet deformation, and inhibit the generation of necking and further expansion