Successful industrial application of superplastic forming (SPF) and superplastic forming/pressure welding (SPF/PW) technologies depends mainly on systematic investigations of superplastic materials, study of their mechanical and technological properties and behavior under conditions of superplastic deformation. This, in turn, is impossible without creating modern techniques and reliable methods for testing sheet materials in conditions of biaxial stress observed during SPF. This paper describes the procedure and equipment for testing sheet billets under conditions of biaxial stress during SPF; the results of test forming operations for titanium and aluminum alloys are presented. The procedure for determining material constants obtained during test forming operations has been developed. Computer simulation of SPF of sheet material has been carried out, the procedure to estimate the friction between the formed material and die has been offered. The effect of friction on polythickness of the formed sheet has been evaluated. The performed research activities have allowed the problem of optimizing the superplastic deformation regimes to be solved.
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