Computer simulation of superplastic forming of a three-sheet structure containing an ultrafine-grained core

Superplastic forming of a three-sheet structure is considered. The focus is on overcoming the main disadvantages of the process of manufacturing of such structures by means of the SPF/DB technique including high temperatures of treatment and the formation of folds on the outer surface of the article manufactured. The application of ultrafine-grained sheets of titanium alloy Ti-6Al-4V has been analyzed in order to avoid these disadvantages. Various combinations of the use of ultrafine-grained and microcrystalline sheets as skin and core sheets are considered by means of the finite element analysis. The standard power law of superplasticity is used for analysis with material constants determined from technological experiments. The conclusion is made that the most attractive way appears to be the usage of ultafine-grained material for the core sheet and microcrystalline material for the skin sheets.