Deformation twinning of Bi–Sb solid alloy formed under a strong gravitational field

Abstract

We performed an ultracentrifuge experiment on Bi–Sb alloy. Deformation twins with misorientations of about 90° were observed in the low-gravitational region where grain refinement had not occurred. The twins were thicker than the conventional deformation twins and their thickness was proportional to the gravitational field. We found that the minimum gravitational field required for grain refinement was 0.17 × 10⁶ G at 240°C for periods <10 h.

Keywords:

• centrifuge
• deformation twinning
• nucleation
• defect
• grain refinement

Acknowledgements

This work was supported in part by the 21st Global COE program of Pulsed Power Science, and the author would like to thank Prof A. Yoshiasa, Institute of Science, Kumamoto University and Mr S. Funaki, Nippon Steel Techno Research for helpful discussions.