Compression testing of superplastic lead–tin eutectic alloy at room temperature

Abstract EN

The deformation behavior of fine grained lead–tin eutectic alloy was investigated at room temperature using compression specimens at initial strain rates in the range 10-5 to 10-1 s-1.

The grain size of the tested specimens was in the range of 2.8 to 7.2 μm.

The results show that the flow stress- strain rate relation could be divided into two distinct regions.

A superplastic region (region II), which prevails at intermediate strain rates, has values of strain rate sensitivity, m and grain size exponent, p of 0.5 and 2.2, respectively.

In dislocation creep region (region III) that dominates at high strain rates values of m and p are 0.11 and 1.6, respectively, and the apparent activation energy is 45 kJmol-1.

Region I that sometimes appears at low strain rates was not observed because a threshold stress is usually not present in high purity alloys such as the one used in this investigation.