Analysis of Void Growth During Superplastic Deformation of Commercial AL5083 Alloy

Superplastic alloys and metals possess the ability to undergo large uniform strains prior to failure. A number of materials are subject to the cavitation during superplastic deformation. Cavitation usually leads to either the undesirable post-forming characteristics or to the premature tensile failure. It is also apparent that the cavities can preexist in the form of cracks and decohered interfaces, which develop during thermo-mechanical processing necessary to produce the superplastic microstructures. Evidently, extensive cavitation imposes significant limitations on their commercial application. The material constitutive equation constants of commercial AL5083 alloy contain strength coefficient, and strain rate sensitivity index is determined by superplastic bulge forming tests for 400, 450, 500, 550 °C. By comparing the results of a deformed sample, good accordance between experimental and FEM results is observed. Using the calculated values for C and m parameters, the effect of material properties such as the cavity growth rate, strain rate sensitivity index, strain hardening exponent and number of intentionally preexisted voids on specimens voids growth subject to the tensile deformation and to the biaxial deformation has been determined numerically. The tensile tests have been simulated by the FEM software ABAQUS v6.9 using commercial aluminum 5083 alloy that presents superplastic properties at temperatures in the range 400–550 °C. The simulations are implemented at 400, 450, 500 and 550 °C. The results of the numerical prediction obtained are in good agreement with the results of the experiments done by some other authors.