Mechanism-based constitutive equations for superplastic forming of TA15 with equiaxed fine grain structure

Universal Multi-objective Function for Optimising Superplastic-damage Constitutive Equations

Based on the dominated deformation mechanisms of superplastic materials, an assumption for micro-damage evolution is presented. Then, a set of uni®ed viscoplastic-damage constitutive equations is proposed to model material hardening due to the increase of dislocation density and grain growth, as well as material softening due to intergranular void nucleation and growth. The effects of the harde...

Finite Element Simulation of Superplastic Forming Using a Microstructure Based Constitutive Model

In this paper, Finite Element simulations using ABAQUS are carried out to optimize and simulate the superplastic forming of Ti-6Al-4V sheet at 900 °C. Microstructure-based constitutive models describing the superplastic deformation are implemented in the FE code through user defined subroutines. Two different forming schemes are used; constant strain rate scheme and optimum variable strain rate...

Cavitation During Superplastic Forming

Cavitation is the opening of pores during superplastic forming, typically at grain boundary triple points or on second phase grain boundary particles during slip of grain boundaries. Theories for the initiation of cavitation are reviewed. It seems that cavitation is unlikely to occur by processes intrinsic to metals such as dislocation mechanisms or point defect condensation. It is proposed tha...

Optimization of Superplastic Forming Technology

The objective of this paper is a superplastic forming (SPF) technologies design and optimization. The conditions of superplasticity are very sensitive to strain rates and temperature characteristic of deformation process. The presented work gives an approach to design the SPF technologies that satisfies such conditions.A possibility to decrease the temperature of the industrial forming of the T...

Analytical and Experimental Investigations on Influential Parameters of Superplastic Forming of Titanium Based Workpieces