Effect of strain rate on the elevated-temperature tensile properties of an AlPb alloy

Abstract

The effect ofPb addition (0.75 wt.%) on the tensile properties of a Al-0.15wt.%Zr alloys has been investigated at a temperature range between 300 and 350 °C. Two strain rates, 10 −4 s −1 and 10 0 s −1, were chosen for this investigation. The important results are summarized as follows. ▪ 1. 1. Pb particles were observed both within Al matrix grains and at grain boundaries. The size of these particles is ~200 nm. 2. 2. At a lower strain rate (10 −4 s −1), a ductile-brittle transition was observed at temperatures between 320 and 330 °C, within which liquid Pb begins to form at grain boundaries. This promotes grain-boundary cavitation and, thus, premature failure. 3. 3. At a high strain rate (10 0 s −1), even at temperatures above the melting point ofPb, grain-boundary cavitation is greatly suppressed and ductility significantly increases. In this case, the fracture of sample is determined by neck instability.