采用CALPHAD(CALculation of PHAse Diagrams)方法重新对Mg-Al-Gd三元系进行评估,获得一套自洽的热力学参数。用Mg_(x)(TM,Mg)_(6)(RE,Mg)_(8)热力学模型(TM=过渡金属,RE=稀土金属)描述长周期堆积有序相14H和18R。计算代表性的等温截面...采用CALPHAD(CALculation of PHAse Diagrams)方法重新对Mg-Al-Gd三元系进行评估,获得一套自洽的热力学参数。用Mg_(x)(TM,Mg)_(6)(RE,Mg)_(8)热力学模型(TM=过渡金属,RE=稀土金属)描述长周期堆积有序相14H和18R。计算代表性的等温截面、垂直截面、液相线投影图和相关的零变量反应,与实验数据进行比较,表明所得热力学参数的可靠性。绘制了整个三元体系的反应图,并对几种Mg-Al-Gd合金的Scheil凝固路径和相分数进行计算和分析,清楚地描述了凝固过程中各相的形成以及γ和LPSO相的相分数随Gd成分的变化,这些是影响Mg-Al-Gd合金的显微硬度、极限抗拉强度和屈服强度的重要因素。展开更多
Y, Gd)Al 3(BO 3) 4∶Eu 3+ samples were prepared by the conventional solid state reaction. The XRD results indicate that the crystal symmetry is low. The excitation spectrum is composed of two broad bands centered ...Y, Gd)Al 3(BO 3) 4∶Eu 3+ samples were prepared by the conventional solid state reaction. The XRD results indicate that the crystal symmetry is low. The excitation spectrum is composed of two broad bands centered at about 170 and 250 nm respectively. In the emission spectra, the peak wavelength is about 616 nm under 147 nm VUV excitation. The luminescent chromaticity coordinate and the relative intensity change along with Gd 3+ mole concentration in the range of 0.15 to 0.85 mol (and Eu 3+ mole concentration, 0.02 to 0.1 mol). The correlative data show that the concentration quenching occurs when the Eu 3+ mole concentration ranges from 0.02 to 0.1 mol, and the Gd 3+→Gd 3+, Gd 3+→Eu 3+ and host→Eu 3+, Gd 3+ energy transfers exist, and Gd 3+ mole concentration influences Eu 3+ emission.展开更多
基金The financial supports from the National Key Laboratory of Science and Technology on High-strength Structural Materialsthe National Natural Science Foundation of China(No.51771235)。
文摘采用CALPHAD(CALculation of PHAse Diagrams)方法重新对Mg-Al-Gd三元系进行评估,获得一套自洽的热力学参数。用Mg_(x)(TM,Mg)_(6)(RE,Mg)_(8)热力学模型(TM=过渡金属,RE=稀土金属)描述长周期堆积有序相14H和18R。计算代表性的等温截面、垂直截面、液相线投影图和相关的零变量反应,与实验数据进行比较,表明所得热力学参数的可靠性。绘制了整个三元体系的反应图,并对几种Mg-Al-Gd合金的Scheil凝固路径和相分数进行计算和分析,清楚地描述了凝固过程中各相的形成以及γ和LPSO相的相分数随Gd成分的变化,这些是影响Mg-Al-Gd合金的显微硬度、极限抗拉强度和屈服强度的重要因素。
基金the financial supports from the Natural Science Foundation of Hunan Province, China (No. 2018JJ2365)the Outstanding Youth Scientific Research Project of Hunan Education Department, China (No. 20B533)+3 种基金the Key Scientific Research Project of Hunan Provincial Department of Education, China (No. 20A455)the Science and Technology Innovation Program of Hunan Province, China (No. 2020RC1011)the Graduate Scientific Research Innovation Project of Hunan Province, China (No. CX20211280)the Science and Technology Innovation Leading Plan of High Tech Industry in Hunan Province, China (No. 2020GK2033)。
文摘Y, Gd)Al 3(BO 3) 4∶Eu 3+ samples were prepared by the conventional solid state reaction. The XRD results indicate that the crystal symmetry is low. The excitation spectrum is composed of two broad bands centered at about 170 and 250 nm respectively. In the emission spectra, the peak wavelength is about 616 nm under 147 nm VUV excitation. The luminescent chromaticity coordinate and the relative intensity change along with Gd 3+ mole concentration in the range of 0.15 to 0.85 mol (and Eu 3+ mole concentration, 0.02 to 0.1 mol). The correlative data show that the concentration quenching occurs when the Eu 3+ mole concentration ranges from 0.02 to 0.1 mol, and the Gd 3+→Gd 3+, Gd 3+→Eu 3+ and host→Eu 3+, Gd 3+ energy transfers exist, and Gd 3+ mole concentration influences Eu 3+ emission.
