Comparative investigations of superplastic behavior and formability of commercial sheets with
microcrystalline (MC, a grain size of 3-5 mm) and submicrocrystalline (SMC, a grain size of
0.3 mm) structure out of titanium Ti-6Al-4V alloy have been performed. It is shown that the
decrease in the grain size leads to a significant decrease in the temperature of superplastic
deformation to 650°C, or to a shift of superplasticity optimum to higher strain rates at
temperatures above 750°C. Unlike commercial sheets, the sheets with SMC structure are
characterized by isotropy of mechanical properties.
The process of superplastic forming (SPF) of sheet samples out of Ti-6Al-4V alloy with SMC
structure in the matrix with the cylindrical hole at the temperature 700°C was investigated. It
has been established that application of material with initial SMC structure provides improving
characteristics of polythickness and decreasing the temperature of SPF by 200°C.
High Performance Metallic Materials for Cost Sensitive Applications