The structural stability, electronic structures, elastic properties and thermodynamic properties of the main binary phases Mg_（17）Al_（12）, Al_2Ca, Mg_2 Sn and Mg_2 Ca in Mg-Al-Ca-Sn alloy were determined from the ...The structural stability, electronic structures, elastic properties and thermodynamic properties of the main binary phases Mg_（17）Al_（12）, Al_2Ca, Mg_2 Sn and Mg_2 Ca in Mg-Al-Ca-Sn alloy were determined from the first-principles calculation. The calculated lattice parameters are in good agreement with the experimental and literature values. The calculated heats of formation and cohesive energies show that Al_2Ca has the strongest alloying ability and structural stability. The densities of states（DOS）, Mulliken electron occupation number, metallicity and charge density difference of these compounds are given. The elastic constants of Mg_（17）Al_（12）, Al_2Ca, Mg_2 Sn and Mg_2 Ca phases are calculated, and the bulk moduli, shear moduli, elastic moduli and Poisson ratio are derived. The calculations of thermodynamic properties show that the Gibbs free energies of Al_2Ca and Mg_2 Sn are lower than that of Mg_（17）Al_（12）, which indicates that Al_2Ca and Mg_2 Sn are more stable than Mg_（17）Al_（12） phase. Hence, the heat resistance of Mg-Al-based alloys can be improved by adding Ca and Sn additions.展开更多
介绍了镁合金的高温蠕变机理和提高镁合金高温蠕变性能应采取的措施,综述了AZ系(Mg Al Zn)、AS系(Mg Al Si)、AE系(Mg Al RE)、AX系(Mg Al Ca)、ACM或MRI系(Mg Al Ca RE)和AJ系(Mg Al Sr)耐热铸造镁合金的研究开发状况及其在汽车上的应...介绍了镁合金的高温蠕变机理和提高镁合金高温蠕变性能应采取的措施,综述了AZ系(Mg Al Zn)、AS系(Mg Al Si)、AE系(Mg Al RE)、AX系(Mg Al Ca)、ACM或MRI系(Mg Al Ca RE)和AJ系(Mg Al Sr)耐热铸造镁合金的研究开发状况及其在汽车上的应用状况,指出了Mg Al系耐热镁合金存在的问题和今后的发展方向。展开更多
基金Project(20131083) supported by the Doctoral Starting up Foundation of Liaoning Province,ClhinaProject(LT201304) supported by the Program for Liaoning Innovative Research Team in University,ChinaProject(2013201018) supported by the Key Technologies Research and Development Program of Liaoning Province,China
文摘The structural stability, electronic structures, elastic properties and thermodynamic properties of the main binary phases Mg_（17）Al_（12）, Al_2Ca, Mg_2 Sn and Mg_2 Ca in Mg-Al-Ca-Sn alloy were determined from the first-principles calculation. The calculated lattice parameters are in good agreement with the experimental and literature values. The calculated heats of formation and cohesive energies show that Al_2Ca has the strongest alloying ability and structural stability. The densities of states（DOS）, Mulliken electron occupation number, metallicity and charge density difference of these compounds are given. The elastic constants of Mg_（17）Al_（12）, Al_2Ca, Mg_2 Sn and Mg_2 Ca phases are calculated, and the bulk moduli, shear moduli, elastic moduli and Poisson ratio are derived. The calculations of thermodynamic properties show that the Gibbs free energies of Al_2Ca and Mg_2 Sn are lower than that of Mg_（17）Al_（12）, which indicates that Al_2Ca and Mg_2 Sn are more stable than Mg_（17）Al_（12） phase. Hence, the heat resistance of Mg-Al-based alloys can be improved by adding Ca and Sn additions.
文摘介绍了镁合金的高温蠕变机理和提高镁合金高温蠕变性能应采取的措施,综述了AZ系(Mg Al Zn)、AS系(Mg Al Si)、AE系(Mg Al RE)、AX系(Mg Al Ca)、ACM或MRI系(Mg Al Ca RE)和AJ系(Mg Al Sr)耐热铸造镁合金的研究开发状况及其在汽车上的应用状况,指出了Mg Al系耐热镁合金存在的问题和今后的发展方向。
