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The microstructure evolution and fracture behavior of Mg-2.7Al-0.8Zn (AZ31B) reinforced with 1 vol% nano silicon-carbide particle (NN-SiCp) and 4 vol% submicron SiCp (SuM-SiCp) during room temperature tensile test were investigated. The tensile failure mechanism of composite in the strain range of 0.8–2.4% were determined using the dislocation studies and microcrack analysis. The addition of double sized SiCp resulted in the extensive accumulation of dislocation near the interface between SiCp and matrix, and the dislocation density is increased as the increase of strain. The formation of high density dislocation zone was identified as one of the main causes of strength enhancement. Some microcracks can be found in the interface between SuM-SiCp and matrix, which show that the high stress concentration exists in the SuM-SiCp/Mg interface due to the particle size and polygonal morphology. However, the bonding interfaces of NN-SiCp/Mg were still continuous, and no microcracks were present around NN-SiCp. As a result of non-deforming SuM-SiCp resisting the crack-propagation, an appreciable crack blunting effect is generated, which contributes to the overall strengthening effect of double sized SiCp/Mg composite. • The deformation/fracture behavior of the magnesium (Mg) matrix composites with nano- and submicron SiCp was investigated. • Interaction between double sized particles and dislocations under tensile deformation was determined. • Strengthening mechanisms of double sized SiCp on tensile properties of composite were determined. [ABSTRACT FROM AUTHOR]

Thermal conductivities of Mg Nd alloys in as-cast, T4 and T6 conditions with Nd content varying from 0 to 12 wt% were studied at room temperature, and corresponding microstructures observation and hardness tests were performed. The as-cast Mg Nd alloys consist of α-Mg and Mg 12 Nd phases, while Mg 12 Nd dissolves into α-Mg matrix or transforms to Mg 41 Nd 5 after T4 treatment. T6 treated Mg Nd alloys are composed of α-Mg and Mg 41 Nd 5 phases. With increasing Nd content, thermal conductivities of Mg Nd alloys all decrease gradually under as-cast, T4 and T6 conditions. The thermal conductivity of as-cast Mg Nd alloys is higher than that of T4 counterparts, while lower than that of corresponding T6 alloys. For T4 alloys, the changes in slopes of Nd content dependence of thermal diffusivity and hardness all occur around the saturated point 0.68 at.% (3.87 wt%), which result from no more Nd atoms dissolved into the Mg matrix with increasing Nd content. Quantitative studies about the influence of solution atoms and second phases on thermal diffusivity were made. The thermal diffusivity increment derived from one atom percentage of Nd addition into the Mg matrix is about 67.24 mm 2 /s while the increment derived from one atom percentage of Nd addition forming second phase is about 11.85 mm 2 /s. [ABSTRACT FROM AUTHOR]

In this study, finite element analysis was performed using representative volume elements (RVE). The cohesive zone model was implemented to govern the failure behavior of the CNTs/matrix interface. The RVE to understand the micromechanical response and damage behavior of randomly distributed carbon nanotubes (CNTs)/Mg matrix composites (MMCs). The cohesive zone model was implemented to govern the failure behavior of the CNTs/Mg interface. The RVE for macroscopic structural analysis was strained under assumed boundary conditions, where it provided a stress-strain curve for the composite. The simulation data can achieve excellent agreement with the experimental results. The simulations and experimental results indicate that the initial damage in the composite occurs in the vicinity of CNTs. The stress concentration at the CNT end increases with the increasing tensile load, resulting in interfacial debonding, the main form of crack growth of the CNTs/Mg composite. The CNTs can passivate the crack tip and change the propagation direction of the main crack, causing a delay in fracture. CNTs played an important role in governing the fracture pattern of composite. The pullout and bridging of CNTs were the main strengthening mechanisms of the composites, which was beneficial for improving strength and toughness. • A smallest RVE as a repeating unit cell (UC) of the material was established to calculating stress-strain curve. • The cohesive zone model was implemented to govern the failure behavior of the CNTs/matrix interface. • The simulation data can achieve excellent agreement with experimental results. • CNTs were effective in pullout and bridging effects for impeding premature failure. [ABSTRACT FROM AUTHOR]

This work investigates the performance of magnesium (Mg) - air battery with modified AZ31 anode, designated as AZ31M. It successfully achieves a high anodic efficiency of 73% with the energy density of 1692 mWh g−1 and capacity of 1582 mAh g−1 at 1 mA cm−2 in 3.5% NaCl. These battery parameters are higher than those reported for most Mg anodes. The addition of the cost-effective La, Ce and Ca refines the bulk Mg 17 Al 12 in AZ31 into small Mg 17 Al 12 , Al 2 Ca and Al 2 (Ca, RE), leading to a uniform discharge with slight galvanic corrosion and low anode delamination effect. The AZ31M anode is a potential candidate Mg anode for wide application of Mg-air battery. [Display omitted] • The AZ31M has homogeneous microstructure with fine second phases distributed uniformly in the matrix. • The Mg-air battery achieves an anodic efficiency of 73% with the energy density of 1692 mWh g−1 at 1 mA cm−2 in 3.5% NaCl. • The corrosion rate of AZ31M is 0.38 ± 0.09 mm y−1 in 3.5 wt% NaCl. • The AZ31M anode is a potential candidate Mg anode for wide application of Mg-air battery. [ABSTRACT FROM AUTHOR]

In this study, the room temperature thermal conductivity and microstructure of Mg−Ce, Mg−Sm and Mg−Y binary alloys in as-cast and solution treated conditions were investigated. Quantitative study was conducted on the effect of rare earth elements (in solid solution and intermetallic compounds) on the thermal conductivity of Mg−RE alloys. The reduction in thermal conductivity was determined to be about 123.0 W/(m·K) and 6.5–16.4 W/(m·K), respectively, per 1 at.% RE addition in the form of solid solution or intermetallic compounds with Mg. The thermal conductivities of Mg−RE alloys were fitted using modified Maxwell and EMT models based on the distribution, volume fractions and shape of intermetallic compounds. The modified structural models provide a good fit to the experimental thermal conductivity data. [ABSTRACT FROM AUTHOR]