Aluminum and its alloys are widely used in packaging, transportation, electrical materials, and many other fields because of their abundance, light weight, good mechanical properties, suitable corrosion resistance, excellent electrical conductivity, and other advantages. Grain refinement achieved by adding inoculant is important not only to reduce the segregation and thermal cracking of alloy castings but also to improve the mechanical properties of alloy castings. Therefore, fine equiaxed grain structure has always been one of the goals pursued by the aluminum alloy casting industry.
View Article and Find Full Text PDFUnderstanding the oxidation process of active metals plays a crucial role in improving their mechanical/oxidation properties. Using in situ environmental transmission electron microscopy and density-functional theory, we firstly clarify the oxidation process of single-crystal Mg at the atomic scale by using a new double-hole technique. A unique incipient interval-layered oxidation mechanism of single-crystal Mg has been confirmed, in which O atoms intercalate through the clean (21[combining macron]1[combining macron]0) surface into the alternate-layered tetrahedral sites, forming a metastable HCP-type MgO structure.
View Article and Find Full Text PDFStructural materials with higher strength and ductility could reduce weight and improve energy efficiency from the ecological and economical viewpoints. However, most classical strengthening strategies, such as refining grain size and forming secondary particles, can effectively hinder dislocation motion but remarkably decrease ductility. In this research, a nanoscale contraction twins-stacking faults (CTWSFs) hierarchical structure was achieved in a model sample of magnesium-lithium (Mg-Li) alloy using an industrial ultrahigh pressure technique.
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