DEFORMATION OF PB-SN EUTECTIC ALLOYS AT RELATIVELY HIGH-STRAIN RATES

The steady-state stresses of lead-tin eutectic alloy (Pb-62Sn) samples of mean phase diameter from 5.5 to 9.9 μm were measured over a range of temperatures from 0° to 160°C and strain rates from 2.66 × 10-5 to 1.33 × 10-2 s-1. The alloy exhibited both conventional and superplastic deformation over this range of experimental variables. The data were consistent with the assumption that the two deformation behaviors occur simultaneously via independent mechanisms. The data may be represented by the dimensionless constitutive relation γ* = 900(τ*)1.96(d*-1.8exp(-11,500/RT) + (1.3 × 1015)(τ*)7.1exp(-19,400/RT), where the first term on the right gives the rate of superplastic deformation and the second term gives the rate of conventional deformation. © 1979.