Kahlenberg, R., Wojcik, T., Falkinger, G., Krejci, A. L., Milkereit, B., & Kozeschnik, E. (2023). On the precipitation mechanisms of β-Mg₂Si during continuous heating of AA6061. Acta Materialia, 261, Article 119345. https://doi.org/10.1016/j.actamat.2023.119345
Aluminum alloys; Differential scanning calorimetry (DSC); In situ transmission electron microscopy (TEM); Precipitate Transformation; Precipitation kinetics
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Abstract:
In the present work, we study the evolution of metastable and Cu-containing precursor precipitates into stable β-Mg₂Si using in-situ transmission electron microscopy during continuous heating of an AA6061 aluminum alloy. The experiments indicate that the transformation into stable β-Mg₂Si involves the release of Al and Cu atoms into the matrix phase combined with the rearrangement of Mg and Si at the interfaces. Nucleation of the β-Mg₂Si precipitates predominantly occurs at the interface between the precursors and the aluminum matrix and at dispersoids. The term precipitate-related transformation is used to emphasize the reaction mechanism, where a new product precipitate nucleates next to a precursor and consumes it at its original location predominantly via interface diffusion. The in-situ investigations are complemented by an analysis of bulk samples and a comparison with differential scanning calorimetry measurements, which show excellent agreement.
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Research facilities:
Universitäre Service-Einrichtung für Transmissionselektronenmikroskopie
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Project title:
Yield Strength Evolution along the Process Chain of selected Al Alloys (AlYield): MCL p3.19 (Materials Center Leoben Forschungs) EFFECTIVE CONSTRUCTION OF PROBABILISTIC HYBRID SEMI-PARAMETRIC MODELS FOR MODEL-BASED CONDITION MONITORING AND ACCELERATED MATERIAL DESIGN: 886385 (FFG - Österr. Forschungsförderungs- gesellschaft mbH)