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Abstract: A particulate reinforced magnesium matrix composite fabricated by stir casting was subjected to multidirectional forging (MDF) at a temperature of 420°C. The results showed that grains of matrix in the composite were significantly refined after 1 MDF pass, and gradually refined till 3 MDF passes. The evolution of particle distribution in the composite during MDF was investigated by a window technique. It was shown that MDF led to an increase of the uniformity of the particle distribution. With increasing the MDF passes, both the tensile strength and the elongation to failure of the composite are significantly enhanced till 3 MDF passes. [ABSTRACT FROM AUTHOR]

Multidirectional forging (MDF) under decreasing temperature conditions was adopted to process SiC nanoparticles reinforced magnesium matrix composite. The results showed that grains of the nanocomposite were effectively refined while the amount of precipitated phases was significantly increased after MDF under decreasing temperature conditions. The precipitated phases as well as dispersed SiC nanoparticles could hinder the growth of dynamic recrystallization. The yield strength and ultimate tensile strength of the nanocomposites were increased compared with that of as-cast nanocomposite. This improvement could be attributed to obvious grain refinement as well as Orowan strengthening effect introduced by the dispersed SiC nanoparticles and the precipitated phases. Microcrack could initiate within the SiC nanoparticle dense zones during tensile test at room temperature, resulting in decrease of the elongation. [ABSTRACT FROM AUTHOR]

Abstract: Carbon nanotube (CNTs) reinforced Mg matrix composites were successfully fabricated by a novel approach. After hot extrusion, the influence of CNTs on microstructure and mechanical properties of Mg–6Zn matrix was investigated. The results showed that most CNTs distributed uniformly and individually in the composites, and good interfacial bonding was achieved. CNTs significantly refined the grains of Mg–6Zn matrix, and the CNTs evidently improved the ultimate tensile strength (UTS), yield strength (YS) and Young's modulus. Grain refinement, load transfer mechanism and Orowan strengthening mechanism play important roles on the increase of the yield strength. [Copyright &y& Elsevier]

sAbstract: The Mg/Al laminated composites were fabricated by the accumulative roll bonding (ARB) at ambient temperature using the pure magnesium and commercial pure Al sheets. Mg grains were refined after the primary sandwich preparation and then homogenized during the following ARB process while the grain size of Al layer decreased with increasing of the accumulated strains. Both the yield strength and ultimate strength along rolling direction and transverse direction increased gradually while the elongation to failure along both directions decreased with increasing of the ARB cycles. Formation of the Mg17Al12 phase indicated that the ARB process at ambient temperature could lead to a metallurgic bonding of the Mg/Al interface. [Copyright &y& Elsevier]

Abstract: In this paper, three kinds of magnesium matrix composites reinforced by SiCp with the sizes of 0.2, 5 and 10μm, respectively, were fabricated by stir casting technology. Then the as-cast ingots were deformed by the combination of forging and extrusion process. Typical microstructures were obtained in the composites reinforced by different particle sizes. For the composites with lower volume fraction of particles (2%), submicron SiCp had significant influence on grain refinement and strengthening effect, which resulted in better mechanical properties of submicron SiCp/AZ91 composite. However, mechanical properties reduced owing to the obvious agglomerated submicron SiC particles as the volume fraction increased to 5% and 10%. On the contrary, for micron SiCp/AZ91 composite, the grain size was refined and the strengthening effect was enhanced with the increasing of volume fraction. Although particle size has no influence on the texture type, it has different effects on weakening the intensity of texture. [Copyright &y& Elsevier]

Abstract: SiCp/AZ91 composites fabricated by stir casting were extruded at different extrusion temperatures and ratios. Extrusion reduced the necklace-type particle distribution and improved particle distribution of the composites. As extrusion temperatures and ratios increased, particle distribution was improved, and the grain sizes of matrix increased. The mechanical properties of the composites were improved with the increase of extrusion temperatures and ratios. The microstructure evolution of matrix was not the main influential factor of the mechanical properties of the composites. The particle evolution, which included particle redistribution and particle cracking induced by extrusion, significantly affected the mechanical properties of the extruded composites. [Copyright &y& Elsevier]

Abstract: In the present study, 10vol.% SiCp/AZ91 magnesium matrix composites are fabricated by stir casting. The as-cast ingots are cut into cylindrical billets, and then forged at 420°C with different deformation amounts (40, 50, 60 and 80%) at a constant RAM speed of 15mm/s. The results illustrate that the addition of SiC particles has significant influence on refining grain size and improving tensile strength of AZ91 matrix, however, weakening basal plane texture. After forging SiCp/AZ91 composites, the intensity of basal plane texture increases as deformation amount increases. The grain size of composite matrix grows up slightly as the deformation amount increased to 60%, and then it was refined obviously as the deformation amount continues to increase to 80%. The smaller deformation amount is propitious to improve particle distribution, while lager deformation amount promotes SiC particle agglomeration. Thus, the tensile strength increases as the deformation amount increases to 50%, however, it decreases as the deformation amount continues to increase to 80%. [Copyright &y& Elsevier]