Journal of Materials Science, Vol.46, No.1, 155-160, 2011
Achieving superplastic properties in a Pb-Sn eutectic alloy processed by equal-channel angular pressing
Experiments were conducted on a Pb-62% Sn eutectic alloy containing 160 ppm of Sb. The alloy was processed by equal-channel angular pressing (ECAP) through 1 to 5 passes at room temperature and then tested in tension at a temperature of 423 K using initial strain rates from 1.0 x 10(-4) to 1.0 x 10(-1) s(-1). Excellent superplastic elongations were achieved at intermediate strain rates with a maximum elongation to failure of 2,665%. It is shown that, for processing through similar numbers of ECAP passes, these elongations are higher than in an earlier investigation using a Pb-62% Sn alloy of higher purity. The results are presented pictorially in the form of a deformation mechanism map by plotting normalized grain size against normalized stress at a temperature of 423 K.