The forming-regions of phosphate glasses doped with high Sm2O3 contents were studied by two step melting method. The relationship between absorption spectrum and rare earth contents was also discussed. The spectra of ...The forming-regions of phosphate glasses doped with high Sm2O3 contents were studied by two step melting method. The relationship between absorption spectrum and rare earth contents was also discussed. The spectra of BASP glasses were measured by spectrophotometer. The results show that the forming regions will shrink with the increase of Al2O3 and it is difficult to form glass when [PO4]/[AlO4] < 2. The forming regions tend to be a closed elliptical, and the intensity of characteristic absorption peak increases gradually with the increase of Sm2O3, the absorption lines broadens non-uniformly and there is approximate linear relation between optical density at the 1064 nm wavelength and Sm2O3 content.展开更多
High entropy metallic glasses（MGs） have attracted tremendous attentions owing to high entropy that benefits the probing of new MG-forming systems. However, the micro-formability of high entropy MGs is lack of invest...High entropy metallic glasses（MGs） have attracted tremendous attentions owing to high entropy that benefits the probing of new MG-forming systems. However, the micro-formability of high entropy MGs is lack of investigation in comparison with these conventional MG counterparts, which is crucial to the development of this kind of metallic alloys. In this work, the thermoplastic mciro-formability of TiZrHfNiCuBe high entropy MG was systemically investigated. Time-Temperature-Transformation（TTT）curve was first constructed based on isothermal crystallization experiments, which provides thermoplastic processing time of the supercooled high entropy MGs. By comparison with the deformation map,Newtonian flow was found beneficial to the thermoplastic formability. While the thermoplastic forming becomes arduous with reducing mould size to tens micrometer, because of the strong supercooled TiZrHfNiCuBe high entropy MG（fragility = 27）. Fortunately, the micro-formability of TiZrHfNiCuBe high entropy MG could be improved by vibration loading, as demonstrated by finite-element-method simulation. Our findings not only systemically evaluate the thermoplastic micro-formability of high entropy MG, but also provide fundamental understanding of the phenomenon.展开更多
Glass formation range of Bi2O3-B2O3-TeO2 system has been investigated （B2O3 ≤ 40 mol%）. Four glasses with compositions xBi2O3-B2O3-（70-x）TeO2 （x = 40, 50, 60 and 70 tool%） have been prepared by using melt quenc...Glass formation range of Bi2O3-B2O3-TeO2 system has been investigated （B2O3 ≤ 40 mol%）. Four glasses with compositions xBi2O3-B2O3-（70-x）TeO2 （x = 40, 50, 60 and 70 tool%） have been prepared by using melt quenching technique. The effect of Bi2O3 content on thermal stability, optical properties and structures of these four Bi2O3-B2O3-TeO2 glasses is systematically investigated by inductive coupled plasma emission spectrometer （ICP）, differential scanning calorimetry （DSC）, Raman spectra and X-ray photoelectron spectroscopy （XPS）. It is found that the density, refractive index and optical basicity increase with increasing Bi2O3. The Raman spectra and XPS spectra show that the glass network is mainly constituted by the [BiO6] octahedron, [TeO4] trigonal bipyramidal, [TeO3] trigonal pyramid, [BO3] trigonal pyramid and [B04] tetrahedron structural units. With increasing Bi2O3, the coordination number around B atom changes from 3 to 4 and [TeO4] units are converted to [TeO3] units. Bi5＋ ions may exist in Bi2O3-B2O3-TeO2 （BBT） system and their amount grows with increasing Bi2O3 content.展开更多
Pd81Si19 amorphous alloys were prepared by combination methods of melt spinning and B2O3 flux treatment. A compari- son between the ribbons prepared from the fluxed ingots and the non-fluxed ones has been carried out....Pd81Si19 amorphous alloys were prepared by combination methods of melt spinning and B2O3 flux treatment. A compari- son between the ribbons prepared from the fluxed ingots and the non-fluxed ones has been carried out. The result reveals that after fluxing treatment the glass transition temperature of the as-prepared glassy ribbons is reduced while the initial crystallization tem- perature is enhanced. It results in that the supercooled liquid region (defined as the difference between the initial crystallization tem- perature and the glass transition temperature) of the glassy alloy treated with fluxing technology has been increased from 31 to 42 K. This shows that fluxing technique can enhance the glass forming ability (GFA) of the binary alloy and improve the thermal stability of supercooled liquid of the glassy alloy.展开更多
采用Zhou W C提出的玻璃形成区研究方法探索了铽硼硅酸盐磁光玻璃形成区域范围,采用魔角核磁共振谱仪(MAS NMR)和示差扫描量热仪(DSC)对玻璃结构和特征温度能进行了表征,研究了Tb2O3和Al2O3对玻璃形成能力和玻璃结构的影响,同时引入玻...采用Zhou W C提出的玻璃形成区研究方法探索了铽硼硅酸盐磁光玻璃形成区域范围,采用魔角核磁共振谱仪(MAS NMR)和示差扫描量热仪(DSC)对玻璃结构和特征温度能进行了表征,研究了Tb2O3和Al2O3对玻璃形成能力和玻璃结构的影响,同时引入玻璃析晶参数β讨论玻璃热稳定性。结果表明:Tb2O3的掺入量受玻璃形成区域的限制,在Tb2O3含量为30%(摩尔分数)时以及Al2O3含量为25%(摩尔分数)时玻璃形成能力较强;铽铝硼硅酸盐玻璃结构中硼氧多面体和铝氧多面体主要以四配位的[BO4]和[AlO4]形式存在,仍存在少量三配位的[BO3]和五配位的[AlO5];Tb2O3含量为30%(摩尔分数)的玻璃β值较大,热稳定性能较好。展开更多
基金Project supported by Research Project (A3820060136)
文摘The forming-regions of phosphate glasses doped with high Sm2O3 contents were studied by two step melting method. The relationship between absorption spectrum and rare earth contents was also discussed. The spectra of BASP glasses were measured by spectrophotometer. The results show that the forming regions will shrink with the increase of Al2O3 and it is difficult to form glass when [PO4]/[AlO4] < 2. The forming regions tend to be a closed elliptical, and the intensity of characteristic absorption peak increases gradually with the increase of Sm2O3, the absorption lines broadens non-uniformly and there is approximate linear relation between optical density at the 1064 nm wavelength and Sm2O3 content.
基金supported by the National Natural Science Foundation of China [Grant Nos. 51671090, 51725504, 51435007]the funds of the the State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology [number AWJ-17M06]
文摘High entropy metallic glasses（MGs） have attracted tremendous attentions owing to high entropy that benefits the probing of new MG-forming systems. However, the micro-formability of high entropy MGs is lack of investigation in comparison with these conventional MG counterparts, which is crucial to the development of this kind of metallic alloys. In this work, the thermoplastic mciro-formability of TiZrHfNiCuBe high entropy MG was systemically investigated. Time-Temperature-Transformation（TTT）curve was first constructed based on isothermal crystallization experiments, which provides thermoplastic processing time of the supercooled high entropy MGs. By comparison with the deformation map,Newtonian flow was found beneficial to the thermoplastic formability. While the thermoplastic forming becomes arduous with reducing mould size to tens micrometer, because of the strong supercooled TiZrHfNiCuBe high entropy MG（fragility = 27）. Fortunately, the micro-formability of TiZrHfNiCuBe high entropy MG could be improved by vibration loading, as demonstrated by finite-element-method simulation. Our findings not only systemically evaluate the thermoplastic micro-formability of high entropy MG, but also provide fundamental understanding of the phenomenon.
基金supported by the National Natural Science Foundation of China(No.60937003)
文摘Glass formation range of Bi2O3-B2O3-TeO2 system has been investigated （B2O3 ≤ 40 mol%）. Four glasses with compositions xBi2O3-B2O3-（70-x）TeO2 （x = 40, 50, 60 and 70 tool%） have been prepared by using melt quenching technique. The effect of Bi2O3 content on thermal stability, optical properties and structures of these four Bi2O3-B2O3-TeO2 glasses is systematically investigated by inductive coupled plasma emission spectrometer （ICP）, differential scanning calorimetry （DSC）, Raman spectra and X-ray photoelectron spectroscopy （XPS）. It is found that the density, refractive index and optical basicity increase with increasing Bi2O3. The Raman spectra and XPS spectra show that the glass network is mainly constituted by the [BiO6] octahedron, [TeO4] trigonal bipyramidal, [TeO3] trigonal pyramid, [BO3] trigonal pyramid and [B04] tetrahedron structural units. With increasing Bi2O3, the coordination number around B atom changes from 3 to 4 and [TeO4] units are converted to [TeO3] units. Bi5＋ ions may exist in Bi2O3-B2O3-TeO2 （BBT） system and their amount grows with increasing Bi2O3 content.
基金This work was financially supported by the National Natural Science Foundation of China (No.50431030, 50671050)the Basic Science Research Foundation of Tsinghua University (No.091201107)the National Center for Nanoscience and Technology of China.
文摘Pd81Si19 amorphous alloys were prepared by combination methods of melt spinning and B2O3 flux treatment. A compari- son between the ribbons prepared from the fluxed ingots and the non-fluxed ones has been carried out. The result reveals that after fluxing treatment the glass transition temperature of the as-prepared glassy ribbons is reduced while the initial crystallization tem- perature is enhanced. It results in that the supercooled liquid region (defined as the difference between the initial crystallization tem- perature and the glass transition temperature) of the glassy alloy treated with fluxing technology has been increased from 31 to 42 K. This shows that fluxing technique can enhance the glass forming ability (GFA) of the binary alloy and improve the thermal stability of supercooled liquid of the glassy alloy.
文摘采用Zhou W C提出的玻璃形成区研究方法探索了铽硼硅酸盐磁光玻璃形成区域范围,采用魔角核磁共振谱仪(MAS NMR)和示差扫描量热仪(DSC)对玻璃结构和特征温度能进行了表征,研究了Tb2O3和Al2O3对玻璃形成能力和玻璃结构的影响,同时引入玻璃析晶参数β讨论玻璃热稳定性。结果表明:Tb2O3的掺入量受玻璃形成区域的限制,在Tb2O3含量为30%(摩尔分数)时以及Al2O3含量为25%(摩尔分数)时玻璃形成能力较强;铽铝硼硅酸盐玻璃结构中硼氧多面体和铝氧多面体主要以四配位的[BO4]和[AlO4]形式存在,仍存在少量三配位的[BO3]和五配位的[AlO5];Tb2O3含量为30%(摩尔分数)的玻璃β值较大,热稳定性能较好。
