Research results on the viscous flow deformation behavior of bulk amorphous alloy in different systems are reviewed. The material exhibits an ideal Newtonian fluid at a high temperature. Analytical solution of lamella...Research results on the viscous flow deformation behavior of bulk amorphous alloy in different systems are reviewed. The material exhibits an ideal Newtonian fluid at a high temperature. Analytical solution of lamellar fluid flow behavior is used to discuss the viscous flow behavior of the bulk amorphous alloy in the supercooled liquid state. A material model, which describes such deformation behavior of Mg6oCusoYlo amorphous alloy, is introduced into the finite element method of microformin8 process. Surface feature size was investigated and found not sensitive to the micro formability. Bulk amorphous alloy may possibly be applied to microelectro-mechanical-systems （MEMS） fabrication.展开更多
The curve of crystallization transition during continuous heating for the Zr41Ti14Cu12.5Ni10Be22.5 bulk amorphous alloy was measured by means of dilatation(Fully automatic transformation recording/measuring instrument...The curve of crystallization transition during continuous heating for the Zr41Ti14Cu12.5Ni10Be22.5 bulk amorphous alloy was measured by means of dilatation(Fully automatic transformation recording/measuring instrument) and X-ray diffraction(XRD) method. The deformation behavior of the alloy at various heating rates in the supercooled liquid region was studied. The results show that the glass transition temperature of the alloy increases slightly and the supercooled liquid region(SLR) increases significantly with increasing heating rate. The deformation amount under isobaric pressure of 1 N for the alloy in the SLR increases with increasing heating rate. As the heating rate of the alloy increases from 5 to 100 ℃/min, the amount of deformation of the alloy increases from 8.3% to 45%.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
The nanocrystallization behaviour of a bulk Zr-based metallic glass subjected to compressive stress is investigated in the supercooled liquid region. Compared with annealing treatments without compressive stress, comp...The nanocrystallization behaviour of a bulk Zr-based metallic glass subjected to compressive stress is investigated in the supercooled liquid region. Compared with annealing treatments without compressive stress, compressive deformation promotes the development of nucleation and suppresses the coarsening of nanocrystallites at high temperatures.展开更多
The master alloy ingots (MAI) with the nominal composition Zr 52.5 Ti 5Cu 17.9 Ni 14.6 Al 10 and Fe 61 Co 7Zr 10 Mo 5W 2B 15 (at%) were prepared by arc melting in Ti gettered Ar atmosphere. The Zr based buttons of 6 m...The master alloy ingots (MAI) with the nominal composition Zr 52.5 Ti 5Cu 17.9 Ni 14.6 Al 10 and Fe 61 Co 7Zr 10 Mo 5W 2B 15 (at%) were prepared by arc melting in Ti gettered Ar atmosphere. The Zr based buttons of 6 mm and 9 mm in diameter were fully amorphous, but those of 13 mm in diameter experienced crystallization. The glass forming ability (GFA) of Fe based alloys was relatively lower, and the buttons obtained were fully crystallized. The microhardness of the Zr based buttons was about 500(Hv), and the Fe based rod obtained by injection technique exhibited a high Vickers hardness of 1329. In addition, an amorphous crystalline transition layers were observed in both the buttons and the rods.展开更多
Amorphous ribbons of Fe 74Al 4Sn 2(PSiB) 20 alloy have been synthesized by melt spinning and axial design method. The thermal properties of the amorphous ribbons have been measured by differential scanning cal...Amorphous ribbons of Fe 74Al 4Sn 2(PSiB) 20 alloy have been synthesized by melt spinning and axial design method. The thermal properties of the amorphous ribbons have been measured by differential scanning calorimeter (DSC). The DSC results show that the Fe 74Al 4Sn 2P 12Si 4B 4 amorphous alloy has relatively wider supercooled liquid region with a temperature interval of 40 38 K (ΔT x=T x-T g). The alloys with a higher phosphorous content in the metalloid element composition triangle of Fe 74Al 4Sn 2(PSiB) 20 have high glass forming ability. The amorphous alloys also show good magnetic properties in which Fe 74Al 4Sn 2P 6 67Si 6 67B 6 67 alloy has a large maximum permeability (μ m), Fe 78Al 4Sn 2P 3Si 3B 10 alloy exhibits a high square ratio (B r/B 10) and Fe 74Al 4Sn 2P 4Si 12B 4 shows a low core loss (P 0 5/1 3T). High glass forming ability and good magnetic properties make Fe 74Al 4Sn 2(PSiB) 20 amorphous alloys valuable in future research.展开更多
利用X射线衍射(XRD)及差热分析(DSC)等方法研究了添加B对Zr Ti Cu Ni Be块状非晶合金的形成、结晶及热稳定性的影响·结果表明:在Zr Ti Cu Ni Be合金系中添加B可明显改变该合金的玻璃转变温度Tg,一次结晶温度Tx及过冷液相区ΔT等参...利用X射线衍射(XRD)及差热分析(DSC)等方法研究了添加B对Zr Ti Cu Ni Be块状非晶合金的形成、结晶及热稳定性的影响·结果表明:在Zr Ti Cu Ni Be合金系中添加B可明显改变该合金的玻璃转变温度Tg,一次结晶温度Tx及过冷液相区ΔT等参数·当y(B)≤3%时,B的添加可使合金保持块状非晶,提高Tg、Tx并扩大过冷液相区,使非晶热稳定性增加;当y(B)≥6%时,B的添加将诱导大量的粗大Zr2Cu及ZrB2等晶体的析出·由于它们非纳米晶,尺寸较大,形状不规整,不能作为非晶复合材料的增强体·展开更多
基金supported by the National Natural Sci-ence Foundation of China under grant No. 50705092.
文摘Research results on the viscous flow deformation behavior of bulk amorphous alloy in different systems are reviewed. The material exhibits an ideal Newtonian fluid at a high temperature. Analytical solution of lamellar fluid flow behavior is used to discuss the viscous flow behavior of the bulk amorphous alloy in the supercooled liquid state. A material model, which describes such deformation behavior of Mg6oCusoYlo amorphous alloy, is introduced into the finite element method of microformin8 process. Surface feature size was investigated and found not sensitive to the micro formability. Bulk amorphous alloy may possibly be applied to microelectro-mechanical-systems （MEMS） fabrication.
文摘The curve of crystallization transition during continuous heating for the Zr41Ti14Cu12.5Ni10Be22.5 bulk amorphous alloy was measured by means of dilatation(Fully automatic transformation recording/measuring instrument) and X-ray diffraction(XRD) method. The deformation behavior of the alloy at various heating rates in the supercooled liquid region was studied. The results show that the glass transition temperature of the alloy increases slightly and the supercooled liquid region(SLR) increases significantly with increasing heating rate. The deformation amount under isobaric pressure of 1 N for the alloy in the SLR increases with increasing heating rate. As the heating rate of the alloy increases from 5 to 100 ℃/min, the amount of deformation of the alloy increases from 8.3% to 45%.
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.
基金Supported by the Science Foundation for Excellent Young Scholars of Heilongjiang Province under Grant No JC-05-11, the Program for New Century Excellent Talents in University of China under Grant No NCET-04-0322, and the Specialized Research Fund for the Doctoral Programme of Higher Education of China under Grant No 20040213049）
文摘The nanocrystallization behaviour of a bulk Zr-based metallic glass subjected to compressive stress is investigated in the supercooled liquid region. Compared with annealing treatments without compressive stress, compressive deformation promotes the development of nucleation and suppresses the coarsening of nanocrystallites at high temperatures.
文摘The master alloy ingots (MAI) with the nominal composition Zr 52.5 Ti 5Cu 17.9 Ni 14.6 Al 10 and Fe 61 Co 7Zr 10 Mo 5W 2B 15 (at%) were prepared by arc melting in Ti gettered Ar atmosphere. The Zr based buttons of 6 mm and 9 mm in diameter were fully amorphous, but those of 13 mm in diameter experienced crystallization. The glass forming ability (GFA) of Fe based alloys was relatively lower, and the buttons obtained were fully crystallized. The microhardness of the Zr based buttons was about 500(Hv), and the Fe based rod obtained by injection technique exhibited a high Vickers hardness of 1329. In addition, an amorphous crystalline transition layers were observed in both the buttons and the rods.
文摘Amorphous ribbons of Fe 74Al 4Sn 2(PSiB) 20 alloy have been synthesized by melt spinning and axial design method. The thermal properties of the amorphous ribbons have been measured by differential scanning calorimeter (DSC). The DSC results show that the Fe 74Al 4Sn 2P 12Si 4B 4 amorphous alloy has relatively wider supercooled liquid region with a temperature interval of 40 38 K (ΔT x=T x-T g). The alloys with a higher phosphorous content in the metalloid element composition triangle of Fe 74Al 4Sn 2(PSiB) 20 have high glass forming ability. The amorphous alloys also show good magnetic properties in which Fe 74Al 4Sn 2P 6 67Si 6 67B 6 67 alloy has a large maximum permeability (μ m), Fe 78Al 4Sn 2P 3Si 3B 10 alloy exhibits a high square ratio (B r/B 10) and Fe 74Al 4Sn 2P 4Si 12B 4 shows a low core loss (P 0 5/1 3T). High glass forming ability and good magnetic properties make Fe 74Al 4Sn 2(PSiB) 20 amorphous alloys valuable in future research.
文摘利用X射线衍射(XRD)及差热分析(DSC)等方法研究了添加B对Zr Ti Cu Ni Be块状非晶合金的形成、结晶及热稳定性的影响·结果表明:在Zr Ti Cu Ni Be合金系中添加B可明显改变该合金的玻璃转变温度Tg,一次结晶温度Tx及过冷液相区ΔT等参数·当y(B)≤3%时,B的添加可使合金保持块状非晶,提高Tg、Tx并扩大过冷液相区,使非晶热稳定性增加;当y(B)≥6%时,B的添加将诱导大量的粗大Zr2Cu及ZrB2等晶体的析出·由于它们非纳米晶,尺寸较大,形状不规整,不能作为非晶复合材料的增强体·
