Effect of Second Phase Particle Size on the Recrystallized Microstructure of Mg–Al Alloys Following ECAE Processing
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Magnesium (Mg) alloys are excellent candidates for structural applications, given their high strength to weight ratios. Grain boundaries and precipitates can both contribute to strengthening in Mg alloys, but the design of high strength Mg alloys is challenging due to Mg’s anisotropic crystal lattice and yield asymmetry. Herein, we focus on thermomechanical processing that involves grain refinement in the presence of precipitates. We seek an understanding of how small and large Mg17Al12 intermetallic particles impact recrystallization and discontinuous precipitation in Mg–Al alloys. We do so by processing solution treated and peak aged Mg–9Al (wt%) alloys using equal channel angular extrusion (ECAE) along the Bc route at 150 °C. We find that the fine nanoprecipitates that nucleate within the solutionized grain interiors during ECAE processing lead to finer Mg grains in the recrystallized regions compared to those in the presence of the long lathlike precipitates produced during peak aging prior to ECAE processing.
KeywordsDeformation processing Nanoprecipitates Nucleation and growth Recrystallization Magnesium alloys
The authors would like to gratefully acknowledge the financial and technical support from the Center for Materials under Extreme Dynamic Environment (CMEDE). The research was sponsored by the Army Research Laboratory and was accomplished under Cooperative Agreement Number W911NF-12-2-0022. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Laboratory or the US Government. The US Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein.
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