High concentration of vacancies induced by β″ phase formation in Al–Mg–Si alloys

ABSTRACT

The high concentration of vacancies induced by β″ phase formation in Al–Mg–Si alloys has been observed by positron annihilation lifetime spectroscopy. These vacancies differ from quenched-in vacancies. The induced vacancies are generated inside or at the interface of the β″ phase, i.e. the β″ phase contains a high concentration of vacancies. The induced vacancies survive during the β″-to-β′ phase transformation. The migration energy of the induced vacancies is determined to be 1.83 ± 0.11 eV, which is about three times higher than that of vacancies in pure Al.

KEYWORDS:

• Positron annihilation spectroscopy
• vacancies
• Al alloys

Acknowledgements

We would like to thank Mrs. Y. Xaio for her support during the experiments and UACJ Corporation for supplying the aluminium alloy.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was partly supported by a Grants-in-Aid for Scientific Research foundation (24246105) from the Japan Society for thePromotion of Science (JSPS) Japan.