The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Choongho Yu - One of the best experts on this subject based on the ideXlab platform.
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Strain-induced suppression of the Miscibility Gap in nanostructured Mg2Si–Mg2Sn solid solutions
Journal of Materials Chemistry, 2020Co-Authors: Suin Yi, Vahid Attari, Myunghwan Jeong, Jie Jian, Haiyan Wang, Raymundo Arroyave, Choongho YuAbstract:Solid solutions of Mg2Si and Mg2Sn are promising thermoelectric materials owing to their high thermoelectric figures-of-merit and non-toxicity, but they may undergo phase separation under thermal cycling due to the presence of Miscibility Gaps, implying that the thermoelectric properties could be significantly degraded during thermoelectric device operation. Herein, this study investigates the strain-induced suppression of the Miscibility Gap in solid solutions of Mg2Si and Mg2Sn. Separately prepared Mg2Si and Mg2Sn powders were made into (Mg2Si)0.7(Mg2Sn)0.3 mixtures using a high energy ball-milling method followed by spark plasma sintering. Afterwards, the phase evolution of the mixtures, depending on thermal annealing and mixing conditions, was studied experimentally and theoretically. Transmission electron microscopy and X-ray diffraction results show that, despite the presence of a Miscibility Gap in the pseudo-binary phase diagram, the initial mixture of Mg2Si and Mg2Sn evolved towards a solid solution state after annealing for 3 hours at 720 °C. Thermodynamic analysis as well as phase-field microstructure simulations show that the strain energy due to the coherent spinodal effect suppresses the chemical spinodal entirely and prevents phase separation. This strategy to suppress the Miscibility Gap induced by lattice strain through non-equilibrium processing can benefit the thermoelectric figure-of-merit by maximizing phonon alloy scattering. Furthermore, stable solid solutions by engineering phase diagrams have the potential to facilitate the reliable long term operation of thermoelectric generators under continuous thermal loads.
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strain induced suppression of the Miscibility Gap in nanostructured mg2si mg2sn solid solutions
Journal of Materials Chemistry, 2018Co-Authors: Suin Yi, Vahid Attari, Myunghwan Jeong, Jie Jian, Haiyan Wang, Raymundo Arroyave, Choongho YuAbstract:Solid solutions of Mg2Si and Mg2Sn are promising thermoelectric materials owing to their high thermoelectric figures-of-merit and non-toxicity, but they may undergo phase separation under thermal cycling due to the presence of Miscibility Gaps, implying that the thermoelectric properties could be significantly degraded during thermoelectric device operation. Herein, this study investigates the strain-induced suppression of the Miscibility Gap in solid solutions of Mg2Si and Mg2Sn. Separately prepared Mg2Si and Mg2Sn powders were made into (Mg2Si)0.7(Mg2Sn)0.3 mixtures using a high energy ball-milling method followed by spark plasma sintering. Afterwards, the phase evolution of the mixtures, depending on thermal annealing and mixing conditions, was studied experimentally and theoretically. Transmission electron microscopy and X-ray diffraction results show that, despite the presence of a Miscibility Gap in the pseudo-binary phase diagram, the initial mixture of Mg2Si and Mg2Sn evolved towards a solid solution state after annealing for 3 hours at 720 °C. Thermodynamic analysis as well as phase-field microstructure simulations show that the strain energy due to the coherent spinodal effect suppresses the chemical spinodal entirely and prevents phase separation. This strategy to suppress the Miscibility Gap induced by lattice strain through non-equilibrium processing can benefit the thermoelectric figure-of-merit by maximizing phonon alloy scattering. Furthermore, stable solid solutions by engineering phase diagrams have the potential to facilitate the reliable long term operation of thermoelectric generators under continuous thermal loads.
Suin Yi - One of the best experts on this subject based on the ideXlab platform.
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Strain-induced suppression of the Miscibility Gap in nanostructured Mg2Si–Mg2Sn solid solutions
Journal of Materials Chemistry, 2020Co-Authors: Suin Yi, Vahid Attari, Myunghwan Jeong, Jie Jian, Haiyan Wang, Raymundo Arroyave, Choongho YuAbstract:Solid solutions of Mg2Si and Mg2Sn are promising thermoelectric materials owing to their high thermoelectric figures-of-merit and non-toxicity, but they may undergo phase separation under thermal cycling due to the presence of Miscibility Gaps, implying that the thermoelectric properties could be significantly degraded during thermoelectric device operation. Herein, this study investigates the strain-induced suppression of the Miscibility Gap in solid solutions of Mg2Si and Mg2Sn. Separately prepared Mg2Si and Mg2Sn powders were made into (Mg2Si)0.7(Mg2Sn)0.3 mixtures using a high energy ball-milling method followed by spark plasma sintering. Afterwards, the phase evolution of the mixtures, depending on thermal annealing and mixing conditions, was studied experimentally and theoretically. Transmission electron microscopy and X-ray diffraction results show that, despite the presence of a Miscibility Gap in the pseudo-binary phase diagram, the initial mixture of Mg2Si and Mg2Sn evolved towards a solid solution state after annealing for 3 hours at 720 °C. Thermodynamic analysis as well as phase-field microstructure simulations show that the strain energy due to the coherent spinodal effect suppresses the chemical spinodal entirely and prevents phase separation. This strategy to suppress the Miscibility Gap induced by lattice strain through non-equilibrium processing can benefit the thermoelectric figure-of-merit by maximizing phonon alloy scattering. Furthermore, stable solid solutions by engineering phase diagrams have the potential to facilitate the reliable long term operation of thermoelectric generators under continuous thermal loads.
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strain induced suppression of the Miscibility Gap in nanostructured mg2si mg2sn solid solutions
Journal of Materials Chemistry, 2018Co-Authors: Suin Yi, Vahid Attari, Myunghwan Jeong, Jie Jian, Haiyan Wang, Raymundo Arroyave, Choongho YuAbstract:Solid solutions of Mg2Si and Mg2Sn are promising thermoelectric materials owing to their high thermoelectric figures-of-merit and non-toxicity, but they may undergo phase separation under thermal cycling due to the presence of Miscibility Gaps, implying that the thermoelectric properties could be significantly degraded during thermoelectric device operation. Herein, this study investigates the strain-induced suppression of the Miscibility Gap in solid solutions of Mg2Si and Mg2Sn. Separately prepared Mg2Si and Mg2Sn powders were made into (Mg2Si)0.7(Mg2Sn)0.3 mixtures using a high energy ball-milling method followed by spark plasma sintering. Afterwards, the phase evolution of the mixtures, depending on thermal annealing and mixing conditions, was studied experimentally and theoretically. Transmission electron microscopy and X-ray diffraction results show that, despite the presence of a Miscibility Gap in the pseudo-binary phase diagram, the initial mixture of Mg2Si and Mg2Sn evolved towards a solid solution state after annealing for 3 hours at 720 °C. Thermodynamic analysis as well as phase-field microstructure simulations show that the strain energy due to the coherent spinodal effect suppresses the chemical spinodal entirely and prevents phase separation. This strategy to suppress the Miscibility Gap induced by lattice strain through non-equilibrium processing can benefit the thermoelectric figure-of-merit by maximizing phonon alloy scattering. Furthermore, stable solid solutions by engineering phase diagrams have the potential to facilitate the reliable long term operation of thermoelectric generators under continuous thermal loads.
Erich H Kisi - One of the best experts on this subject based on the ideXlab platform.
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on sun testing of Miscibility Gap alloy thermal storage
Solar Energy, 2019Co-Authors: Mark Copus, Alexander Post, Heber Sugo, Dylan Cuskelly, James Bradley, Samuel Reed, Benjamin Fraser, Roger Reece, Stuart Hands, Erich H KisiAbstract:Abstract The ability of a C-Zn Miscibility Gap Alloy (MGA) material to operate as a combined solar receiver and storage was investigated. MGA thermal energy storage materials comprise metallic PCM particles embedded within a conducting metal or semi-metal matrix to form a macroscopically solid combined latent heat/sensible heat storage material. A receiver containing 4 × 1L MGA storage modules was mounted on a solar concentrating dish. The storage material was directly illuminated by concentrated solar radiation at a flux of approximately 105 kW/m2, readily attaining surface temperatures of 520–530 °C, well above the phase change temperature of 420 °C. Single step charging led to a state of charge of 80% without exceeding a nominal surface temperature of 530 °C. Cycling on and off sun in the range 460–520 °C was used to achieve a state of 99% charged. Thermal performance of the MGA during solar charging and its discharge by natural cooling is presented and analysed.
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Miscibility Gap alloys a new thermal energy storage solution
2018Co-Authors: Erich H Kisi, Anthony Rawson, Heber Sugo, Dylan Cuskelly, Mark Copus, James Bradley, Thomas Fiedler, Alex Post, Samuel ReedAbstract:The status of Miscibility Gap alloys (MGA), which have demonstrated excellent characteristics for thermal storage applications over a wide range of temperatures, is reviewed. MGA remain macroscopically solid whilst delivering latent heat from embedded metal particles supplemented by the sensible heat of the whole material. Heat can be delivered rapidly due to very high thermal conductivity leading to modular solid storage designs which can act as solar boilers for direct steam CSP or other applications. Progress in the manufacture, alloy design and a demonstration of 1.5 kW steam turbine generator with integrated MGA storage unit are briefly described.
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scaling up Miscibility Gap alloy thermal storage materials
2018Co-Authors: Mark Copus, Heber Sugo, Erich H Kisi, Samuel Reed, James BradleyAbstract:Miscibility Gap alloys (MGAs) are a new thermal storage technology that utilises the latent heat of fusion of metals. MGAs encapsulate the liquid phase while maintaining high thermal conductivity, resulting in a safe and effective method of thermal storage. In order to develop MGA to a stage where it can be useful in an industry setting, production and size need to be enlarged greatly. This study attempts several methods of increasing the size of MGA storage blocks. The resulting C-Zn MGA storage blocks have a volume of 0.58 L, which are capable of storing 0.34 MJ of highly dispatchable thermal energy.
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price estimation for Miscibility Gap alloy thermal storage systems
Renewable Energy and Environmental Sustainability, 2017Co-Authors: Alexander Post, Anthony Rawson, Heber Sugo, Dylan Cuskelly, Mark Copus, James Bradley, Erich H KisiAbstract:Miscibility Gap alloys (MGAs) are an emerging thermal energy storage material with unique thermal properties that may be of particular interest to the renewable energy industry. In this study, they are compared to state of the art thermal storage technologies on an economic basis, with consideration given to material prices, manufacturing costs, specific deployment infrastructure costs, maintenance schedule cost and the potential for material salvage. Cost estimates are provided for seven different MGAs deployed in three different thermal storage implementations.
Rachel Orenstein - One of the best experts on this subject based on the ideXlab platform.
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solid solution formation in mg2 si sn and shape of the Miscibility Gap
Acta Materialia, 2020Co-Authors: Mohammad Yasseri, Aryan Sankhla, Hasbuna Kamila, Rachel Orenstein, D Nhi Y Truong, Nader Farahi, Johannes De BoorAbstract:Abstract Investigation of the thermochemical stability of Mg2(Si,Sn) thermoelectric materials is crucial for further development of thermoelectric modules. There is a Miscibility Gap reported for the quasibinary Mg2Si–Mg2Sn series, though the exact compositions of its limits are disputed. Gaining a better understanding of intersolubility limits in Mg2(Si,Sn) is important for further optimization of material performance by exploiting the Gap-induced phase segregation. For a better understanding on the boundaries of the Miscibility Gap below 700°C, two approaches were taken to provide evidence of thermodynamic stable phases and, hereby, monitor the borders of the Miscibility Gap. The approaches cover the homogenization of Mg2SixSn1-x at 700°C and diffusion couple experiments at 600°C, 525°C, and 450°C. For 600°C we find two ranges where Mg2Si and Mg2Sn are not miscible, namely x = 0.35 ± 0.05 and x = 0.75 ± 0.05 for Miscibility Gap I and 0.85 ± 0.05
Mohammad Yasseri - One of the best experts on this subject based on the ideXlab platform.
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solid solution formation in mg2 si sn and shape of the Miscibility Gap
Acta Materialia, 2020Co-Authors: Mohammad Yasseri, Aryan Sankhla, Hasbuna Kamila, Rachel Orenstein, D Nhi Y Truong, Nader Farahi, Johannes De BoorAbstract:Abstract Investigation of the thermochemical stability of Mg2(Si,Sn) thermoelectric materials is crucial for further development of thermoelectric modules. There is a Miscibility Gap reported for the quasibinary Mg2Si–Mg2Sn series, though the exact compositions of its limits are disputed. Gaining a better understanding of intersolubility limits in Mg2(Si,Sn) is important for further optimization of material performance by exploiting the Gap-induced phase segregation. For a better understanding on the boundaries of the Miscibility Gap below 700°C, two approaches were taken to provide evidence of thermodynamic stable phases and, hereby, monitor the borders of the Miscibility Gap. The approaches cover the homogenization of Mg2SixSn1-x at 700°C and diffusion couple experiments at 600°C, 525°C, and 450°C. For 600°C we find two ranges where Mg2Si and Mg2Sn are not miscible, namely x = 0.35 ± 0.05 and x = 0.75 ± 0.05 for Miscibility Gap I and 0.85 ± 0.05