|About this Abstract
||2010 TMS Annual Meeting & Exhibition
||Computational Thermodynamics and Kinetics
||A MIXED-MODE MODEL FOR PRECIPITATION IN AL-MG-SI ALLOYS
||Abbas Bahrami, Alexis Miroux, Jilt Sietsma, Leo Kestens
|On-Site Speaker (Planned)
A modified Kampmann-Wagner numerical (KWN) precipitation model has been developed considering the mixed-mode character of precipitate growth. The η-parameter, which is proportional to the diffusivity of the diffusing alloying element and inversely proportional to the mobility of interface and to the radius of precipitates, is used to implement the character of precipitate growth into the kinetic model. The effects of interfacial energy, diffusivity, and interface mobility on the character and kinetics of precipitation in Al-Mg-Si system have been systematically studied. The results show that the interfacial energy has almost no effect on the precipitation character. However, diffusivity and interface mobility have significant influences on the character of precipitation. The results also show that when the alloying element is interstitial, the alloy is heavily-deformed before ageing, or precipitates are very small with coherent interface, the assumption of mixed-mode growth is more accurate than the assumption of diffusion-controlled growth.
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