Numerical simulation and experimental trials on superplastic forming for thin-walled structure of Ti2AINb alloy

Abstract

Abstract. The difficult formability of Ti2AlNb alloy leads to the difficulty of traditional manufacturing methods to form the complex thin-walled components, limiting the wide application of Ti2AlNb alloy in aerospace. In this paper the superplastic forming process of Ti2AINb alloy with thin-walled structure was studied. The superplastic tensile tests of Ti2AINb alloy were carried out at varying temperature ranging from 920℃ to 980℃ and strain rate ranging from 0.001s-1 to 0.03s-1. The effect of the deformation-temperature and strain rate on the superplastic deformation behaviour was analysed, showing that the flow stress and elongation increase with the increasing temperature and the flow stress decreases, the elongation increases with the decrease of the strain rate. The elongation reaches the maximum value of 525% at the temperature of 940℃ and the strain rate of 0.001s-1. The constitutive equation taking into account the effect of strain was developed, which was implemented into the FE-based software Abaqus to simulate the superplastic forming of the thin-walled structure. The optimal values of the slab thickness and loading pressure-time curve were obtained by simulation and the superplastic forming tests of thin-walled structure were performed. The comparison between the numerical and experimental data with regard to thickness variation verified the accuracy of the finite element model. The research results provide a reference basis for the preparation of complex thin-walled structures of Ti2AINb alloy in aerospace.