The as-cast microstructure of Mg-5Al-3Ca-xNd alloys consists of equiaxed -Mg matrix, (Mg, Al) 2 Ca eutectic phase and Al-Nd rich intermetallic compounds. With the increase of Nd addition, -Mg matrix morphology was changed from dendritic to equiaxed grains due to suppression of grain growth by formation of homogeneous intermetallic compounds containing Nd dispersed at grain boundary and -Mg matrix. And the grain size of as-cast alloys was decreased as addition of Nd was increased. This eutectic phase of the extruded alloys was elongated to extrusion direction and size of this phase was redined comparing to that of as-cast alloys because of severe deformation during hot extrusion. Maximum yield and ultimate tensile strength value of the as-extruded alloys was 322 and 335 MPa at Mg-5Al-3Ca-2Nd alloy, respectively.
In this study, the following conclusions were obtained from an investigation of the effect of the simulation time step on the simulation results of the two-dimensional, vertically averaged sediment transport model SED2D and an analysis of the deposited sediment distribution in suspended sediments of reservoirs according to grain size. The simulation time step has a significant effect on the deposited sediment distribution in a reservoir. In particular, if the simulation time step is set to be excessively large, physically invalid results are obtained. Additionally, in order to determine an appropriate simulation time step for SED2D, the selection of a simulation time step that will allow the analysis of the suspended sediment concentration profile at the main points of the simulation domain is necessary. The deposited sediment distribution in a reservoir according to grain size, including suspended sediments of clay, silt, and sand, was successfully simulated. Such information will prove valuable in application to the establishment of efficient management and reduction measures of reservoir sediment deposits.
The thermal conductivities of binary Mg-CaO and Mg-Zn, and ternary Mg-Zn-CaO alloys have been investigated by evaluating the effect of CaO on pure Mg and Mg-Zn alloys, with an emphasis to develop a new Mg alloy by compromising thermal conductivity, process-ability and mechanical property. The Mg alloys specimens were prepared by casting into a steel mold and then by machining. The thermal conductivities of the alloys were determined by evaluating the thermal properties of specific heat and diffusivity, from room temperature to 200 °C. OM, SEM, and EDS were used to analyze the microstructures and phases. The fluidity was also investigated by using a spiral fluidity mold for improved process-ability during actual die casting.
AZ31 Mg / 5083 Al clad sheet was fabricated by the hot rolling method and its
mechanical properties were investigated in this study. The tensile strength and yield strength of Mg-
Al clad samples were slightly higher than that of AZ31 Mg sample, resulting in high strength 5083
Al alloy. Also, in the case of the AZ31 Mg sample, tensile strength indicated different values to the
rolling directions. The thickness of interface layers between magnesium and aluminum materials
increased with increasing rolling temperature. The thickness of interface layer was about 1.2 μm
and 1.6 μm, respectively. The difference of thickness on the interface layer with variation of rolling
temperature was attributed to promote the diffusion between magnesium and aluminum materials.
The Vickers hardness of Mg-Al interface layer was around 125 Hv. The interface layer composed
of hard inter-metallic phases which may act a increment of Vickers hardness depending upon its
thickness.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.