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S.f. Hsieh - One of the best experts on this subject based on the ideXlab platform.
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Transformation Sequence and second phases in ternary ti ni w shape memory alloys with less than 2 at w
Journal of Alloys and Compounds, 2005Co-Authors: S.f. Hsieh, H.c. Lin, C.h. YangAbstract:Abstract Transformation Sequence and second phases in Ti 50− X Ni 50 W X , Ti 50 Ni 50− X W X and Ti 51 Ni 49− X W X alloys with X = 1–2 at.% are investigated. Two different second-phase particles located at grain boundaries are observed. The lattice parameters of Ti 50 Ni 49 W 1 martensite are calculated from the selected area diffraction patterns (SADP) and all of them are larger than those of Ti 50 Ni 50 alloy. Experimental results indicate that the W atoms replace Ni atoms, instead of Ti ones in these alloys. In addition, Ti 50− X Ni 50 W X and Ti 51 Ni 49− X W X alloys have a two-stage B2 → R → B19′ Transformation, but the Ti 50 Ni 50− X W X alloy has a one-stage B2 → B19′ Transformation because the former Ms temperatures are depressed significantly. The shape recovery of these alloys can be improved by the W solid-solution hardening. With higher matrix hardness in these alloys, there is better shape recovery.
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Transformation Sequence and second phases in ternary Ti–Ni–W shape memory alloys with less than 2 at.% W
Journal of Alloys and Compounds, 2004Co-Authors: S.f. Hsieh, H.c. Lin, C.h. YangAbstract:Abstract Transformation Sequence and second phases in Ti 50− X Ni 50 W X , Ti 50 Ni 50− X W X and Ti 51 Ni 49− X W X alloys with X = 1–2 at.% are investigated. Two different second-phase particles located at grain boundaries are observed. The lattice parameters of Ti 50 Ni 49 W 1 martensite are calculated from the selected area diffraction patterns (SADP) and all of them are larger than those of Ti 50 Ni 50 alloy. Experimental results indicate that the W atoms replace Ni atoms, instead of Ti ones in these alloys. In addition, Ti 50− X Ni 50 W X and Ti 51 Ni 49− X W X alloys have a two-stage B2 → R → B19′ Transformation, but the Ti 50 Ni 50− X W X alloy has a one-stage B2 → B19′ Transformation because the former Ms temperatures are depressed significantly. The shape recovery of these alloys can be improved by the W solid-solution hardening. With higher matrix hardness in these alloys, there is better shape recovery.
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A study on the nickel-rich ternary Ti–Ni–Al shape memory alloys
Journal of Materials Science, 1997Co-Authors: S.f. HsiehAbstract:The Transformation Sequence and hardening effects of 400 °C aged Ti47.5Ni50.65Al1.85 and Ti49.5Ni50.13Al0.37 shape memory alloys have been investigated by electrical resistivity tests, internal friction measurements, hardness tests and TEM observations. Both solution hardening and precipitation hardening are found to occur in these alloys. The hardening effects of Ti47.5Ni50.65Al1.85 alloy are obvious and much higher than those of Ti49.5Ni50.13Al0.37 alloy due to the former having the larger Ni/Ti ratio and a higher Al solute content in its matrix. The Transformation Sequence of 400 °C aged Ti47.5Ni50.65Al1.85 alloy shows B2↔R-phase only for an ageing time of more than 10 h and that of 400°C aged Ti49.5Ni50.13Al0.37 alloy shows the Sequence B2↔R-phase↔B19′ or B2↔R-phase with different ageing times. All of these characteristics are associated with Ti11Ni14 precipitates during the ageing process. These aged Ti–Ni–Al alloys exhibit very good shape memory effects, in which the maximal shape recovery occurs at the peak of hardness.
Wei Huang - One of the best experts on this subject based on the ideXlab platform.
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a facile and green approach to synthesize mesoporous anatase tio2 nanomaterials for efficient dye sensitized and hole conductor free perovskite solar cells
ACS Sustainable Chemistry & Engineering, 2018Co-Authors: Liang Chu, Wei Liu, Rui Zhang, Jian Yang, Wei Huang, Jie ZhangAbstract:Mesoporous anatase TiO2 nanomaterials (MATNs) with both large specific surface areas and structural coherence are highly desirable to achieve excellent physicochemical properties for photovoltaic applications, but the existing synthesis methods either need templates or cause pollution. Herein we report a simple, template-free, and green approach to synthesize MATNs consisting of interconnected nanoparticles. The Ti-complex intermediates were first prepared using titanium isopropoxide and acetic acid in a solvothermal reaction, which went through a morphology Transformation Sequence of nanowires, microspheres, and microflowers with a prolonged reaction time. Then the Ti-complex intermediates were cracked into MATNs under annealing, which were applied in dye-sensitized solar cells (DSSCs) and hole-conductor-free perovskite solar cells (HPSCs). The mesoporous anatase TiO2 nanowire-based DSSCs achieved a high power conversion efficiency (PCE) up to 7.78% because of both a high dye-adsorption capacity and long...
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A Facile and Green Approach to Synthesize Mesoporous Anatase TiO2 Nanomaterials for Efficient Dye-Sensitized and Hole-Conductor-Free Perovskite Solar Cells
2018Co-Authors: Liang Chu, Wei Liu, Rui Zhang, Jian Yang, Jie Zhang, Wei HuangAbstract:Mesoporous anatase TiO2 nanomaterials (MATNs) with both large specific surface areas and structural coherence are highly desirable to achieve excellent physicochemical properties for photovoltaic applications, but the existing synthesis methods either need templates or cause pollution. Herein we report a simple, template-free, and green approach to synthesize MATNs consisting of interconnected nanoparticles. The Ti-complex intermediates were first prepared using titanium isopropoxide and acetic acid in a solvothermal reaction, which went through a morphology Transformation Sequence of nanowires, microspheres, and microflowers with a prolonged reaction time. Then the Ti-complex intermediates were cracked into MATNs under annealing, which were applied in dye-sensitized solar cells (DSSCs) and hole-conductor-free perovskite solar cells (HPSCs). The mesoporous anatase TiO2 nanowire-based DSSCs achieved a high power conversion efficiency (PCE) up to 7.78% because of both a high dye-adsorption capacity and long charge-transfer channels, while the PCE based on the P25 photoelectrodes is 6.61%. The further application of mesoporous anatase TiO2 nanowires in HPSCs achieved an improved PCE of 8.52%, compared to 6.78% for cells prepared using the P25 electrodes
N. Prabhu - One of the best experts on this subject based on the ideXlab platform.
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Microstructural studies on phase evolution Sequence in rapidly solidified Zr3Al based binary and ternary alloys
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2001Co-Authors: R. Tewari, G.k. Dey, N. PrabhuAbstract:Abstract Transformation Sequences in the alloys Zr 3 Al, Zr 3 Al–3Nb and Zr 3 Al–10Nb are described and rationalized in terms of some basic tendencies such as phase separation and chemical ordering in the β phase and displacive omega and β→α (h.c.p.) Transformations. These alloys were melt-spun and aged at different temperatures to study the evolution of different phases. The rapidly solidified Zr 3 Al alloy showed the presence of an amorphous phase or of a spinodally decomposed microstructure depending upon the severity of quenching, whereas the microstructure of the Zr 3 Al–3Nb and the Zr 3 Al–10Nb alloys exhibited a distribution of cuboidal particles (D8 8 phase) in the β matrix. Ageing of these alloys showed the formation of several metastable phases prior to the formation of equilibrium phase. The Transformation Sequence was found to involve a gradual filling of the open structure into a close packed configuration without reconstruction of the lattice.
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Microstructural studies on phase evolution Sequence in rapidly solidified Zr3Al based binary and ternary alloys
Materials Science and Engineering: A, 2001Co-Authors: R. Tewari, G.k. Dey, N. PrabhuAbstract:Transformation Sequences in the alloys Zr3Al, Zr3Al–3Nb and Zr3Al–10Nb are described and rationalized in terms of some basic tendencies such as phase separation and chemical ordering in the β phase and displacive omega and β→α (h.c.p.) Transformations. These alloys were melt-spun and aged at different temperatures to study the evolution of different phases. The rapidly solidified Zr3Al alloy showed the presence of an amorphous phase or of a spinodally decomposed microstructure depending upon the severity of quenching, whereas the microstructure of the Zr3Al–3Nb and the Zr3Al–10Nb alloys exhibited a distribution of cuboidal particles (D88 phase) in the β matrix. Ageing of these alloys showed the formation of several metastable phases prior to the formation of equilibrium phase. The Transformation Sequence was found to involve a gradual filling of the open structure into a close packed configuration without reconstruction of the lattice.© Elsevie
C.h. Yang - One of the best experts on this subject based on the ideXlab platform.
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Transformation Sequence and second phases in ternary ti ni w shape memory alloys with less than 2 at w
Journal of Alloys and Compounds, 2005Co-Authors: S.f. Hsieh, H.c. Lin, C.h. YangAbstract:Abstract Transformation Sequence and second phases in Ti 50− X Ni 50 W X , Ti 50 Ni 50− X W X and Ti 51 Ni 49− X W X alloys with X = 1–2 at.% are investigated. Two different second-phase particles located at grain boundaries are observed. The lattice parameters of Ti 50 Ni 49 W 1 martensite are calculated from the selected area diffraction patterns (SADP) and all of them are larger than those of Ti 50 Ni 50 alloy. Experimental results indicate that the W atoms replace Ni atoms, instead of Ti ones in these alloys. In addition, Ti 50− X Ni 50 W X and Ti 51 Ni 49− X W X alloys have a two-stage B2 → R → B19′ Transformation, but the Ti 50 Ni 50− X W X alloy has a one-stage B2 → B19′ Transformation because the former Ms temperatures are depressed significantly. The shape recovery of these alloys can be improved by the W solid-solution hardening. With higher matrix hardness in these alloys, there is better shape recovery.
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Transformation Sequence and second phases in ternary Ti–Ni–W shape memory alloys with less than 2 at.% W
Journal of Alloys and Compounds, 2004Co-Authors: S.f. Hsieh, H.c. Lin, C.h. YangAbstract:Abstract Transformation Sequence and second phases in Ti 50− X Ni 50 W X , Ti 50 Ni 50− X W X and Ti 51 Ni 49− X W X alloys with X = 1–2 at.% are investigated. Two different second-phase particles located at grain boundaries are observed. The lattice parameters of Ti 50 Ni 49 W 1 martensite are calculated from the selected area diffraction patterns (SADP) and all of them are larger than those of Ti 50 Ni 50 alloy. Experimental results indicate that the W atoms replace Ni atoms, instead of Ti ones in these alloys. In addition, Ti 50− X Ni 50 W X and Ti 51 Ni 49− X W X alloys have a two-stage B2 → R → B19′ Transformation, but the Ti 50 Ni 50− X W X alloy has a one-stage B2 → B19′ Transformation because the former Ms temperatures are depressed significantly. The shape recovery of these alloys can be improved by the W solid-solution hardening. With higher matrix hardness in these alloys, there is better shape recovery.
R. Tewari - One of the best experts on this subject based on the ideXlab platform.
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Microstructural studies on phase evolution Sequence in rapidly solidified Zr3Al based binary and ternary alloys
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2001Co-Authors: R. Tewari, G.k. Dey, N. PrabhuAbstract:Abstract Transformation Sequences in the alloys Zr 3 Al, Zr 3 Al–3Nb and Zr 3 Al–10Nb are described and rationalized in terms of some basic tendencies such as phase separation and chemical ordering in the β phase and displacive omega and β→α (h.c.p.) Transformations. These alloys were melt-spun and aged at different temperatures to study the evolution of different phases. The rapidly solidified Zr 3 Al alloy showed the presence of an amorphous phase or of a spinodally decomposed microstructure depending upon the severity of quenching, whereas the microstructure of the Zr 3 Al–3Nb and the Zr 3 Al–10Nb alloys exhibited a distribution of cuboidal particles (D8 8 phase) in the β matrix. Ageing of these alloys showed the formation of several metastable phases prior to the formation of equilibrium phase. The Transformation Sequence was found to involve a gradual filling of the open structure into a close packed configuration without reconstruction of the lattice.
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Microstructural studies on phase evolution Sequence in rapidly solidified Zr3Al based binary and ternary alloys
Materials Science and Engineering: A, 2001Co-Authors: R. Tewari, G.k. Dey, N. PrabhuAbstract:Transformation Sequences in the alloys Zr3Al, Zr3Al–3Nb and Zr3Al–10Nb are described and rationalized in terms of some basic tendencies such as phase separation and chemical ordering in the β phase and displacive omega and β→α (h.c.p.) Transformations. These alloys were melt-spun and aged at different temperatures to study the evolution of different phases. The rapidly solidified Zr3Al alloy showed the presence of an amorphous phase or of a spinodally decomposed microstructure depending upon the severity of quenching, whereas the microstructure of the Zr3Al–3Nb and the Zr3Al–10Nb alloys exhibited a distribution of cuboidal particles (D88 phase) in the β matrix. Ageing of these alloys showed the formation of several metastable phases prior to the formation of equilibrium phase. The Transformation Sequence was found to involve a gradual filling of the open structure into a close packed configuration without reconstruction of the lattice.© Elsevie
