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Adding various amounts of nano-sized TiC p (0.1–0.7 wt%) made a simultaneous improvement in high-temperature strength and ductility of the Al-Cu matrix alloy. The influences of temperature and strain rate on the high-temperature tensile properties and θ′ precipitate sizes in the Al-Cu matrix alloy and the nano-sized TiC p /Al-Cu composites were investigated. Theoretical calculations suggest that the yield strength increment of the composites at 453 K was primarily attributed to the strengthening effect of both the refined θ′ precipitates and TiC p , while at 493 K only the strengthening effect of TiC p was predominant due to the significant coarsening of θ′ precipitates at this temperature. [ABSTRACT FROM AUTHOR]

In the present study, Mg-6Zn-1Zr (ZK60) alloy with a homogeneous fine-grained structure (~5 µm) was produced by hot extrusion. The influence of temperature on tensile properties anisotropy and the associated change in deformation mechanisms in the range of 25–275 °C of the fine-grained ZK60 alloy were investigated. Under room temperature, the fine-grained ZK60 alloy exhibited a high tensile strength of ~269–327 MPa and high ductility of ~15–39% when tested at three different directions, indicating a high anisotropy. With increasing testing temperature to 150 °C and further to 275 °C, the alloy showed a gradual decrease in anisotropy. Especially, the fine-grained ZK60 alloy exhibited superplasticity of ~376–434% when tested at 275 °C, which should be due to the increasing role of grain boundary sliding (GBS), as the strong basal texture associated with room temperature deformation became almost random at elevated temperatures. Moreover, the abrupt decrease in tensile anisotropy and associated change in texture with increasing temperature correlates closely to the transformation of deformation mode from a dislocation-dominated behavior to a GBS-mediated one. [ABSTRACT FROM AUTHOR]

We report a new rolling route combining one pass of hard-plate rolling and two passes of conventional rolling. This route is efficient in achieving near-spherical Mg 17 Al 12 phase (~0.5 µm) and uniform fine-grained structure (~3 µm) featuring a weakened texture in AZ91-0.4Sn plates after a total thickness reduction of ~86.4% via 3 rolling passes. Moreover, the processed alloy exhibited superplasticity-like fracture strain of ~96% at 200 °C, owing to fine α-Mg grains distributed with a high volume fraction of Mg 17 Al 12 . This new route significantly reduces rolling passes and hence has a great potential for industrial production. [ABSTRACT FROM AUTHOR]

Inspired by nacre, we designed biomimetic metal–ceramic composites in which hard and ductile phases were alternately arranged. We first prepared lamellar-structured TiC scaffolds with 25, 30 and 35 vol% solid loadings using a unidirectional freeze casting technique and then measured wetting and infiltration dynamics for a commercial Al cast alloy, ZL107, with the main composition of Al–7Si–5Cu on the porous TiC scaffold using a modified sessile drop method at 850 °C. The wetting was affected by liquid spreading at horizontal surface and infiltration in depth, while the latter played a dominant role in the decrease in contact angle. On the basis of the wetting results, the lamellar ZL107/TiC composites were successfully fabricated by pressure infiltration of the molten ZL107 alloy into porous TiC scaffolds and their mechanical properties were evaluated. The compressive strength and elastic modulus increased while bending strength decreased with increasing TiC content, giving maximum values of 1166 ± 20 MPa, 205 ± 2 GPa and 363 ± 5 MPa, respectively. Formation of (Al m ,Si 1 − m ) 3 Ti, Al 3 Ti and Al 4 C 3 phases in the composites was presumed to deteriorate the toughness of the composites, leading to brittle fracture under loading. [ABSTRACT FROM AUTHOR]

Abstract: A first-principles method was performed to calculate generalized stacking fault (GSF) energies in Mg alloys with Sn, Pb and Sn+Pb dopings for acting as references of designing Mg–Sn–Pb alloys. We clarify the effect of Sn is dominated than Pb atom on reduced unstable stacking fault energy ( ), especially in basal and pyramidal slip systems. Such a reduction of non-basal slip GSF energy is in favor of improving the ductility of Mg matrix. [Copyright &y& Elsevier]

Schmid factors (m) for typical slip modes (basal 〈a〉, prismatic 〈a〉, pyramidal 〈a〉 and 〈c + a〉 slips) and twinning patterns ( and twins) were systematically calculated in hexagonal close-packed Cd, Zn, Mg, Zr, Ti and Be. A monotonic effect on m-values was presented for pyramidal 〈a〉 and 〈c + a〉 slips, and and twinning patterns with decreasing c/a ratio. The results calculated herein were used to characterize deformation behaviors and provide essential data for anisotropic feature analysis. [ABSTRACT FROM AUTHOR]

Generalized stacking fault energies of magnesium without and with Al and Sn dopings were studied using first-principles calculations to investigate mechanisms of improved ductility for a new Mg–3Al–3Sn alloy. Reduced unstable stacking fault energy (γus ) results in the improved activity of and the activation of the and slip systems. Moreover, the lower γus of than of leads to the replacement of the latter by the former to be the second primary slip system. [ABSTRACT FROM AUTHOR]