An examination of strain weakening and self-annealing in a Bi-Sn alloy processed by high-pressure torsion

The high pressure torsion (HPT) process was performed on a Bi-Sn eutectic alloy up to 10 revolutions and the materials were stored at room temperature for durations up to 91 days in order to investigate the strain weakening and self-annealing behaviour of the alloy. The results show that HPT processing leads to significant grain refinement and enhanced superplasticity in the alloy. When the material is stored at room temperature, the grain size increases and the microhardness also increases producing a near linear relationship between grain size and microhardncess. This effect is attributed to the enhanced creep behaviour of the Bi-Sn alloy after HPT processing