The microstructure evolution of Mg-Al-Ca alloys modified by the addition of strontium was investigated. It was found that Sr addition leads to the coarsening of α-Mg matrix. However, with the Sr content increasing fr...The microstructure evolution of Mg-Al-Ca alloys modified by the addition of strontium was investigated. It was found that Sr addition leads to the coarsening of α-Mg matrix. However, with the Sr content increasing from 0.1% to 0.5%, the grain size decreases from 83.9 to 65.8 μm. The addition of Sr ranging from 0.1% to 0.3% refines the Al2Ca phase. It changes the morphology of the Al2Ca phase from bone-shaped to granular or banding, and increases its volume fraction. The decrease of grain size of the α-Mg matrix is due to the increase of the effective undercooling degree of the melt and the constitutional undercooling in a diffusion layer ahead of the advancing solid/liquid interface in the alloy modified by the Sr additions. The modification mechanism of Al2Ca is attributed to the adsorption of Sr additions to the Al2Ca crystal. When the Sr content increases to 0.5%, the alloy is over-modified.展开更多
基金financially supported by the Russian Science Foundation(No.20-19-00746)(SEM,DSC,thermodynamic calculations)the federal academic leadership program Priority 2030 of NUST MISIS(DFT,XRD)。
基金Project(51075132)supported by the National Natural Science Foundation of ChinaProject(9451806001002350)supported by Guangdong Science Fund+2 种基金Project(30815007)supported by the Science Fund of State Key Laboratory of Advanced Design and Manufacturing for Vehicle BodyProject(09JJ1007)supported by Hunan Science Fund for Distinguished Young ScholarsProject(20090161110027)supported by the Doctoral Fund of Ministry of Education of China
文摘The microstructure evolution of Mg-Al-Ca alloys modified by the addition of strontium was investigated. It was found that Sr addition leads to the coarsening of α-Mg matrix. However, with the Sr content increasing from 0.1% to 0.5%, the grain size decreases from 83.9 to 65.8 μm. The addition of Sr ranging from 0.1% to 0.3% refines the Al2Ca phase. It changes the morphology of the Al2Ca phase from bone-shaped to granular or banding, and increases its volume fraction. The decrease of grain size of the α-Mg matrix is due to the increase of the effective undercooling degree of the melt and the constitutional undercooling in a diffusion layer ahead of the advancing solid/liquid interface in the alloy modified by the Sr additions. The modification mechanism of Al2Ca is attributed to the adsorption of Sr additions to the Al2Ca crystal. When the Sr content increases to 0.5%, the alloy is over-modified.
