Abstract: 00Cr25Ni7Mo3N duplex stainless steel was treated by different solutions,its super plastic deformation was tested on an isothermal tensile machine,and the diffusion bonding by super plastic deformation was performed on a Gleeble 3500 thermal simulator.The solution treated microstructures and the bonding interface voids were observed by scanning electron microscopy(SEM).The results indicate that the volume ratio of α phase to γ phase(x_α/x_γ) varies with the solution temperature.During the tensile process,the elongation and the peak stress increase with the initial value of x_α/x_γ increasing under the same deformation condition.The elongation of the specimen solution-treated at 1 350℃ reaches to 1 186% at a deformation temperature of 960℃ and a strain rate of 1×10^-3s^-1.At a bonding temperature of 1 100℃ the diffusion bonding mechanism depends on loading modes,but the influence of loading modes on the interfacial shear strength is not significant.During the bonding,the closure degree and retention position of the interfacial voids are related with the relative migration velocity of grain boundaries.