Several 35CrMo4 and 38MnV7 steels with different additions of Ti and V were manufactured by electroslag remelting. The influence of the alloying and microalloying elements on phase transformation at different cooling ...Several 35CrMo4 and 38MnV7 steels with different additions of Ti and V were manufactured by electroslag remelting. The influence of the alloying and microalloying elements on phase transformation at different cooling rates was studied and the continuous cooling transformation diagrams were plotted. In order to optimize the heat treatment and improve the mechanical properties, the range of cooling rates leading to a fully bainitic microstructure （without ferrite, pearlite and especially without martensite） was determined. Bainite and martensite transformation start temperatures （Bs, Ms） were also established and compared with the values predicted by empirical equations. The important role of precipitates （especially V carbonitride particles） on final microstructure and mechanical properties was assessed.展开更多
In the present work,the nature of phase evolution of(1x)(Na_(0.5)Bi_(0.5))TiO_(3)-xSrTiO_(3)(NBT-xST)solid solutions with x of 0e0.6 is revealed by characterizing the dielectric and ferroelectric properties.Two unique...In the present work,the nature of phase evolution of(1x)(Na_(0.5)Bi_(0.5))TiO_(3)-xSrTiO_(3)(NBT-xST)solid solutions with x of 0e0.6 is revealed by characterizing the dielectric and ferroelectric properties.Two unique dielectric anomalies associated with high-temperature nanoregions(PNRs)in the ergodic relaxor(ER)state and low-temperature PNRs in the nonergodic relaxor(NR)state are identified.Characteristic temperatures,including TB,TRT*,Tm,Td and TT*,are determined in fresh and poled states on the basis of the characteristics of the evolution of these two dielectric anomalies.The whole evolution of the transition from the NR state to the ER state is reflected by the temperature-dependent polarization versus electric field(P-E)hysteresis loops,i.e.,from the square loops,via the double-like loops,to the slim loops.The characteristic temperatures,including TP-N,TN-R and TR-dis,are determined by the characteristics of the evolution of P-E loops.Accordingly,a phase diagram of NBT-xST was constructed according to these characteristic temperatures.Most importantly,the relationship between polarization responses and heterogeneous polar phase coexistence has been established and a schematic diagram is given.This work will help to understand the phase evolution and its impact on the macroscopic properties of NBT and the associated NBT-based solid solutions.展开更多
As the basis of modern industry, the roles materials play are becoming increasingly vital in this day and age. With many superior physical properties over conventional fluids, the low melting point liquid metal materi...As the basis of modern industry, the roles materials play are becoming increasingly vital in this day and age. With many superior physical properties over conventional fluids, the low melting point liquid metal material, especially room-temperature liquid metal, is recently found to be uniquely useful in a wide variety of emerging areas from energy, electronics to medical sciences. However, with the coming enormous utilization of such materials, serious issues also arise which urgently need to be addressed. A biggest concern to impede the large scale application of room-temperature liquid metal technologies is that there is currently a strong shortage of the materials and species available to meet the tough requirements such as cost, melting point, electrical and thermal conductivity, etc. Inspired by the Material Genome Initiative as issued in 2011 by the United States of America, a more specific and focused project initiative was proposed in this paper--the liquid metal material genome aimed to discover advanced new functional alloys with low melting point so as to fulfill various increasing needs. The basic schemes and road map for this new research program, which is expected to have a worldwide significance, were outlined. The theoretical strategies and experimental methods in the research and development of liquid metal material genome were introduced. Particularly, the calculation of phase diagram （CALPHAD） approach as a highly effective way for material design was discussed. Further, the first-principles （FP） calculation was suggested to combine with the statistical thermo- dynamics to calculate the thermodynamic functions so as to enrich the CALPHAD database of liquid metals. When the experimental data are too scarce to perform a regular treatment, the combination of FP calculation, cluster variation method （CVM） or molecular dynamics （MD）, and CALPHAD, referred to as the mixed FP-CVM- CALPHAD method can be a promising way to solve the problem. Except for the theoretical strategies, severa展开更多
Conventionally, an experimentally determined phase diagram requires studies of phase formation at a range of temperatures for each composition, which takes years of effort from multiple research groups. Combinatorial ...Conventionally, an experimentally determined phase diagram requires studies of phase formation at a range of temperatures for each composition, which takes years of effort from multiple research groups. Combinatorial materials chip technology, featuring high-throughput synthesis and characterization, is able to determine the phase diagram of an entire composition spread of a binary or ternary system at a single temperature on one materials library, which, though significantly increasing efficiency, still requires many libraries processed at a series of temperatures in order to complete a phase diagram. In this paper, we propose a "one-chip method" to construct a complete phase diagram by individually synthesizing each pixel step by step with a progressive pulse of energy to heat at different temperatures while monitoring the phase evolution on the pixel in situ in real time. Repeating this process pixel by pixel throughout the whole chip allows the entire binary or ternary phase diagram to be mapped on one chip in a single experiment. The feasibility of this methodology is demonstrated in a study of a Ge-Sb-Te ternary alloy system, on which the amorphouscrystalline phase boundary is determined.展开更多
The aim of this study is to synthesize the catalysts of Fe- and Mn-substituted hexaaluminate by reverse microemulsion medium for methane catalytic combustion application. Pseudo-ternary phase diagrams in quaternary mi...The aim of this study is to synthesize the catalysts of Fe- and Mn-substituted hexaaluminate by reverse microemulsion medium for methane catalytic combustion application. Pseudo-ternary phase diagrams in quaternary microemulsion systems of cetyltrimethylammonium bromide (CTAB), n-butanol, n-octane, and water [or Al(NO3)3 solution] were presented. The effects of the alcohol chain length, ratio of sur-factant to cosurfactant, and salt concentration on the formation and stability of microemulsion systems were studied. The phase behavior of microemulsion systems was confirmed through the varying of the conductivity with the water content. The performance and structure of the catalysts, La(Mn x /Fe x )Al12?x ? O19-δ synthesized with the optimal parameter in the phase diagrams of microemulsions systems were characterized by BET, TG-DTA, and XRD. The micro fix-bed reactor was used to measure the catalytic activities of catalysts to methane combustion. The results showed that this synthesis method could yield non-agglomerated and highly dispersed precursors that would undergo crystallization at the lower temperature of 950°C. When temperature was raised up to 1050°C, the complete crystalline La-hexaaluminate was shaped. The hexaaluminate substituted with Fe had high-catalytic activity and stability at high temperature, while the Mn-substituted had higher catalytic activity at lower temperature. When the cooperation of Fe and Mn occurred, i.e., LaFeMnAl10O19?δ exhibited a high surface area and catalytic activity to CH4 combustion, the CH4 light-off temperature was only 475°C and the complete combustion temperature was 660°C. This was attributed to the synergistic effect between Fe and Mn.展开更多
Solubilities of ternary systems Li+,K+/SO42--H2O (1) and Li+,Mg2+/SO42-H2O (2) were investigated by isothermal method at 25℃. Physico-chemical properties of solutions, such as density, refractive index, viscosity, c... Solubilities of ternary systems Li+,K+/SO42--H2O (1) and Li+,Mg2+/SO42-H2O (2) were investigated by isothermal method at 25℃. Physico-chemical properties of solutions, such as density, refractive index, viscosity, conductivity and pH, were determined. Phase diagram of the system (1) consists of three solubility branches and three crystallization fields corresponding to K2SO4, Li2SO4.H2O and LiKSO4. LiKSO4 is an incongruent compound, and its transition point is estimated graphically to be 45.5-46.0℃. No solid solution of LiKSO4 with Li2SO4.H2O was found in the system. The system (2) is a simple eutonic type. Pitzer model of electrolyte solution was used to check the obtained solubilities. Data comparison gives good agreement. Two equations were used to correlate density, refractive index of the solution with its composition. Differences between measured and calculated values are less than 0.6% for density, 0.15% for the latter.展开更多
Solid-liquid phase equilibria of the two ternary systems （NaCl＋SrCl2＋H2O） and （KCl＋SrCl2＋H2O） at T=288.15 K and p=0.1 MPa were studied using the isothermal dissolution equilibritma method. Solubilities of the ...Solid-liquid phase equilibria of the two ternary systems （NaCl＋SrCl2＋H2O） and （KCl＋SrCl2＋H2O） at T=288.15 K and p=0.1 MPa were studied using the isothermal dissolution equilibritma method. Solubilities of the equilibrium liquid phase were determined, and the solids were also investigated by the Schreinemaker method of wet residues. In the ternary system （NaCl＋SrCl2＋H2O） at 288.15 K, there is one invariant point corresponding to （NaCl＋SrCl2-6H2O） and two crystallization regions corresponding to NaC1 and SrCl2-6H2O. The crystallized area of SrCl2-6H2O decreased with the increasing temperature, while that of NaCl increased slightly. In the ternary system （KCl＋SrCl2＋H2O） at 288.15 K, there is one invariant point（KCl＋SrCl2.6H2O） and two crystallization regions cor- responding to KCl and SrCl2· 6H2O. Both systems belong to a simple eutectic type, and neither double salts nor solid solutions were formed. On the basis of Pitzer-Harvie-Weare model, the solubilities of the two systems at 288.15 K were demonstrated. A comparison showed that the calculated solubilities agreed well with the experimental data.展开更多
A phase diagram was drawn through thermodynamic calculation to understand the equilibrium conditions of 2MgO · SiO2 , MgO · Al2O3 , 3Al2O3 · 2SIO2, and 2MgO·2Al2O3 · 5SiO2 formation in Mg-AI-S...A phase diagram was drawn through thermodynamic calculation to understand the equilibrium conditions of 2MgO · SiO2 , MgO · Al2O3 , 3Al2O3 · 2SIO2, and 2MgO·2Al2O3 · 5SiO2 formation in Mg-AI-Si-O system of 430 stainless steel melts at 1873 K. Further, the thermodynamic formation and transformation conditions of MgO · Al2O3 inclusion were discussed. The following results are obtained when ws, =0.26% and wo = 1.0 × 10^-5 in molten steel. The uniphase cordierite inclusion is difficult to exist stably; MgO· At203 inclusion cannot he formed in case of wAl being less than 1× 10^- 6 ; 3Al2O3 · 2SiO2 would change to MgO· Al2O3 and 2MgO · SiO2 in turn with increasing the Mg content when wAl is above 1.7× 10^- 6 ; with the formation of MgO · Al2O3 inclusion, A1 content increases with increasing Mg content when wMg is over 1. 7 × 10^- 9. For equilibrium condition and calculated steel composition, 2MgO·SiO2 inclusion would be formed ultimately and MgO · Al2O3 is almost inexistent.展开更多
The solid-liquid equilibria in the quinary system Na^＋, K^＋//CI^-, SO4^2-, B4O7^2- -H2O at 298 K had been studied experimentally using the method of isothermal solution saturation. Solubilities and densities of the...The solid-liquid equilibria in the quinary system Na^＋, K^＋//CI^-, SO4^2-, B4O7^2- -H2O at 298 K had been studied experimentally using the method of isothermal solution saturation. Solubilities and densities of the solution of the quinary system were measured experimentally. Based on the experimental data, the dry-salt phase diagram and water content diagram of the quinary system were constructed, respectively. In the equilibrium diagram of the quinary system Na^＋, K^＋//CI^-, SO4^2-, B4O7^2- -H2O at 298 K, there are five invariant points F1, F2, F3, F4 and F5; eleven univariant curves ELF1, E2F2, E3F3, E4F5, E5F2, E6F4, E7F5, F1F4, F2F4 F1F3 and F3F5, and seven fields of crystallization saturated with Na2B407 corresponding to Na2SO4, Na2SO4·10H2O, NazSO4-3K2SO4 （Gla）, K2SO4, K2B4O7·4H2O, NaC1 and KC1. The experimental results show that Na2SO4＂3KzSO4 （Gla）, K2SO4 and K2B4O7·4H2O have bigger crystallization fields than other salts in the quinary system Na^＋, K^＋//CI^-, SO4^2-, B4O7^2- -H2O at 298 K.展开更多
基金the financial support of Spanish Ministry of Economy and Competitiveness through the project ref.MAT2011-29039-C02-02
文摘Several 35CrMo4 and 38MnV7 steels with different additions of Ti and V were manufactured by electroslag remelting. The influence of the alloying and microalloying elements on phase transformation at different cooling rates was studied and the continuous cooling transformation diagrams were plotted. In order to optimize the heat treatment and improve the mechanical properties, the range of cooling rates leading to a fully bainitic microstructure （without ferrite, pearlite and especially without martensite） was determined. Bainite and martensite transformation start temperatures （Bs, Ms） were also established and compared with the values predicted by empirical equations. The important role of precipitates （especially V carbonitride particles） on final microstructure and mechanical properties was assessed.
基金the National Natural Science Foundation of China(Grant nos.51672226,51772239)the Fundamental Research Funds for the Central Universities(XJTU).
文摘In the present work,the nature of phase evolution of(1x)(Na_(0.5)Bi_(0.5))TiO_(3)-xSrTiO_(3)(NBT-xST)solid solutions with x of 0e0.6 is revealed by characterizing the dielectric and ferroelectric properties.Two unique dielectric anomalies associated with high-temperature nanoregions(PNRs)in the ergodic relaxor(ER)state and low-temperature PNRs in the nonergodic relaxor(NR)state are identified.Characteristic temperatures,including TB,TRT*,Tm,Td and TT*,are determined in fresh and poled states on the basis of the characteristics of the evolution of these two dielectric anomalies.The whole evolution of the transition from the NR state to the ER state is reflected by the temperature-dependent polarization versus electric field(P-E)hysteresis loops,i.e.,from the square loops,via the double-like loops,to the slim loops.The characteristic temperatures,including TP-N,TN-R and TR-dis,are determined by the characteristics of the evolution of P-E loops.Accordingly,a phase diagram of NBT-xST was constructed according to these characteristic temperatures.Most importantly,the relationship between polarization responses and heterogeneous polar phase coexistence has been established and a schematic diagram is given.This work will help to understand the phase evolution and its impact on the macroscopic properties of NBT and the associated NBT-based solid solutions.
文摘As the basis of modern industry, the roles materials play are becoming increasingly vital in this day and age. With many superior physical properties over conventional fluids, the low melting point liquid metal material, especially room-temperature liquid metal, is recently found to be uniquely useful in a wide variety of emerging areas from energy, electronics to medical sciences. However, with the coming enormous utilization of such materials, serious issues also arise which urgently need to be addressed. A biggest concern to impede the large scale application of room-temperature liquid metal technologies is that there is currently a strong shortage of the materials and species available to meet the tough requirements such as cost, melting point, electrical and thermal conductivity, etc. Inspired by the Material Genome Initiative as issued in 2011 by the United States of America, a more specific and focused project initiative was proposed in this paper--the liquid metal material genome aimed to discover advanced new functional alloys with low melting point so as to fulfill various increasing needs. The basic schemes and road map for this new research program, which is expected to have a worldwide significance, were outlined. The theoretical strategies and experimental methods in the research and development of liquid metal material genome were introduced. Particularly, the calculation of phase diagram （CALPHAD） approach as a highly effective way for material design was discussed. Further, the first-principles （FP） calculation was suggested to combine with the statistical thermo- dynamics to calculate the thermodynamic functions so as to enrich the CALPHAD database of liquid metals. When the experimental data are too scarce to perform a regular treatment, the combination of FP calculation, cluster variation method （CVM） or molecular dynamics （MD）, and CALPHAD, referred to as the mixed FP-CVM- CALPHAD method can be a promising way to solve the problem. Except for the theoretical strategies, severa
基金supported in part by National High Technology Research and Development Program (2015AA034204)the National Natural Science Foundation of China (51472044)
文摘Conventionally, an experimentally determined phase diagram requires studies of phase formation at a range of temperatures for each composition, which takes years of effort from multiple research groups. Combinatorial materials chip technology, featuring high-throughput synthesis and characterization, is able to determine the phase diagram of an entire composition spread of a binary or ternary system at a single temperature on one materials library, which, though significantly increasing efficiency, still requires many libraries processed at a series of temperatures in order to complete a phase diagram. In this paper, we propose a "one-chip method" to construct a complete phase diagram by individually synthesizing each pixel step by step with a progressive pulse of energy to heat at different temperatures while monitoring the phase evolution on the pixel in situ in real time. Repeating this process pixel by pixel throughout the whole chip allows the entire binary or ternary phase diagram to be mapped on one chip in a single experiment. The feasibility of this methodology is demonstrated in a study of a Ge-Sb-Te ternary alloy system, on which the amorphouscrystalline phase boundary is determined.
基金Supported by the National Natural Science Foundation of China (No. 20706004)Beijing Natural Science Foundation (Nos. 2062017 and 8072018)
文摘The aim of this study is to synthesize the catalysts of Fe- and Mn-substituted hexaaluminate by reverse microemulsion medium for methane catalytic combustion application. Pseudo-ternary phase diagrams in quaternary microemulsion systems of cetyltrimethylammonium bromide (CTAB), n-butanol, n-octane, and water [or Al(NO3)3 solution] were presented. The effects of the alcohol chain length, ratio of sur-factant to cosurfactant, and salt concentration on the formation and stability of microemulsion systems were studied. The phase behavior of microemulsion systems was confirmed through the varying of the conductivity with the water content. The performance and structure of the catalysts, La(Mn x /Fe x )Al12?x ? O19-δ synthesized with the optimal parameter in the phase diagrams of microemulsions systems were characterized by BET, TG-DTA, and XRD. The micro fix-bed reactor was used to measure the catalytic activities of catalysts to methane combustion. The results showed that this synthesis method could yield non-agglomerated and highly dispersed precursors that would undergo crystallization at the lower temperature of 950°C. When temperature was raised up to 1050°C, the complete crystalline La-hexaaluminate was shaped. The hexaaluminate substituted with Fe had high-catalytic activity and stability at high temperature, while the Mn-substituted had higher catalytic activity at lower temperature. When the cooperation of Fe and Mn occurred, i.e., LaFeMnAl10O19?δ exhibited a high surface area and catalytic activity to CH4 combustion, the CH4 light-off temperature was only 475°C and the complete combustion temperature was 660°C. This was attributed to the synergistic effect between Fe and Mn.
基金supported by the National Natural Science Foundation of China.
文摘 Solubilities of ternary systems Li+,K+/SO42--H2O (1) and Li+,Mg2+/SO42-H2O (2) were investigated by isothermal method at 25℃. Physico-chemical properties of solutions, such as density, refractive index, viscosity, conductivity and pH, were determined. Phase diagram of the system (1) consists of three solubility branches and three crystallization fields corresponding to K2SO4, Li2SO4.H2O and LiKSO4. LiKSO4 is an incongruent compound, and its transition point is estimated graphically to be 45.5-46.0℃. No solid solution of LiKSO4 with Li2SO4.H2O was found in the system. The system (2) is a simple eutonic type. Pitzer model of electrolyte solution was used to check the obtained solubilities. Data comparison gives good agreement. Two equations were used to correlate density, refractive index of the solution with its composition. Differences between measured and calculated values are less than 0.6% for density, 0.15% for the latter.
基金Supported by the National Natural Science Foundation of China（Nos.21406048, U1507109）, the Natttral Science Foundation of Hebei Province, China（No.B2017202198）, and the Natural Science Foundation of Tianjin, China（Nos.17JCYBJC19500, 15JCQNJC06100）.
文摘Solid-liquid phase equilibria of the two ternary systems （NaCl＋SrCl2＋H2O） and （KCl＋SrCl2＋H2O） at T=288.15 K and p=0.1 MPa were studied using the isothermal dissolution equilibritma method. Solubilities of the equilibrium liquid phase were determined, and the solids were also investigated by the Schreinemaker method of wet residues. In the ternary system （NaCl＋SrCl2＋H2O） at 288.15 K, there is one invariant point corresponding to （NaCl＋SrCl2-6H2O） and two crystallization regions corresponding to NaC1 and SrCl2-6H2O. The crystallized area of SrCl2-6H2O decreased with the increasing temperature, while that of NaCl increased slightly. In the ternary system （KCl＋SrCl2＋H2O） at 288.15 K, there is one invariant point（KCl＋SrCl2.6H2O） and two crystallization regions cor- responding to KCl and SrCl2· 6H2O. Both systems belong to a simple eutectic type, and neither double salts nor solid solutions were formed. On the basis of Pitzer-Harvie-Weare model, the solubilities of the two systems at 288.15 K were demonstrated. A comparison showed that the calculated solubilities agreed well with the experimental data.
基金Item Sponsored by National Natural Science Foundation of China (50704010)
文摘A phase diagram was drawn through thermodynamic calculation to understand the equilibrium conditions of 2MgO · SiO2 , MgO · Al2O3 , 3Al2O3 · 2SIO2, and 2MgO·2Al2O3 · 5SiO2 formation in Mg-AI-Si-O system of 430 stainless steel melts at 1873 K. Further, the thermodynamic formation and transformation conditions of MgO · Al2O3 inclusion were discussed. The following results are obtained when ws, =0.26% and wo = 1.0 × 10^-5 in molten steel. The uniphase cordierite inclusion is difficult to exist stably; MgO· At203 inclusion cannot he formed in case of wAl being less than 1× 10^- 6 ; 3Al2O3 · 2SiO2 would change to MgO· Al2O3 and 2MgO · SiO2 in turn with increasing the Mg content when wAl is above 1.7× 10^- 6 ; with the formation of MgO · Al2O3 inclusion, A1 content increases with increasing Mg content when wMg is over 1. 7 × 10^- 9. For equilibrium condition and calculated steel composition, 2MgO·SiO2 inclusion would be formed ultimately and MgO · Al2O3 is almost inexistent.
基金Project supported by the National Natural Science Foundation of China （No. 40973047）, the New Century Excellent Talents in Universities of China （No. NCET-07-0125） and the Young Science Foundation of Sichuan Province in China （No. 08ZQ026-017）.
文摘The solid-liquid equilibria in the quinary system Na^＋, K^＋//CI^-, SO4^2-, B4O7^2- -H2O at 298 K had been studied experimentally using the method of isothermal solution saturation. Solubilities and densities of the solution of the quinary system were measured experimentally. Based on the experimental data, the dry-salt phase diagram and water content diagram of the quinary system were constructed, respectively. In the equilibrium diagram of the quinary system Na^＋, K^＋//CI^-, SO4^2-, B4O7^2- -H2O at 298 K, there are five invariant points F1, F2, F3, F4 and F5; eleven univariant curves ELF1, E2F2, E3F3, E4F5, E5F2, E6F4, E7F5, F1F4, F2F4 F1F3 and F3F5, and seven fields of crystallization saturated with Na2B407 corresponding to Na2SO4, Na2SO4·10H2O, NazSO4-3K2SO4 （Gla）, K2SO4, K2B4O7·4H2O, NaC1 and KC1. The experimental results show that Na2SO4＂3KzSO4 （Gla）, K2SO4 and K2B4O7·4H2O have bigger crystallization fields than other salts in the quinary system Na^＋, K^＋//CI^-, SO4^2-, B4O7^2- -H2O at 298 K.
