Diffusion on Demand to Control Precipitation Aging: Application to Al-Mg-Si Alloys

We demonstrate experimentally that a part-per-million addition of Sn solutes in Al-Mg-Si alloys can inhibit natural aging and enhance artificial aging. The mechanism controlling the aging is argued to be vacancy diffusion, with solutes trapping vacancies at low temperature and releasing them at elevated temperature, which is supported by a thermodynamic model and first-principles computations of Sn-vacancy binding. This "diffusion on demand" solves the long-standing problem of detrimental natural aging in Al-Mg-Si alloys, which is of great scientific and industrial importance. Moreover, the mechanism of controlled buffering and release of excess vacancies is generally applicable to modulate diffusion in other metallic systems.


Published in:
Physical Review Letters, 112, 22
Year:
2014
Publisher:
College Pk, American Physical Society
ISSN:
0031-9007
Laboratories:




 Record created 2014-10-23, last modified 2018-09-13


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