Cubic boron nitride and hexagonal boron nitride are the two predominant crystalline structures of boron nitride.They can interconvert under varying pressure and temperature conditions.However,this transformation requi...Cubic boron nitride and hexagonal boron nitride are the two predominant crystalline structures of boron nitride.They can interconvert under varying pressure and temperature conditions.However,this transformation requires overcoming significant potential barriers in dynamics,which poses great difficulty in determining the c-BN/h-BN phase boundary.This study used high-pressure in situ differential thermal measurements to ascertain the temperature of h-BN/c-BN conversion within the commonly used pressure range(3-6 GPa)for the industrial synthesis of c-BN to constrain the P-T phase boundary of h-BN/c-BN in the pressure-temperature range as much as possible.Based on the analysis of the experimental data,it is determined that the relationship between pressure and temperature conforms to the following equation:P=a+1/bT.Here,P denotes the pressure(GPa)and T is the temperature(K).The coefficients are a=-3.8±0.8 GPa and b=229.8±17.1 GPa/K.These findings call into question existing high-pressure and high-temperature phase diagrams of boron nitride,which seem to overstate the phase boundary temperature between c-BN and h-BN.The BN phase diagram obtained from this study can provide critical temperature and pressure condition guidance for the industrial synthesis of c-BN,thus optimizing synthesis efficiency and product performance.展开更多
By using CALPHAD (Calculation of Phase Diagram) technique the optimization and calculation of the binary systems of TbCl_3-ACl (A= Li, Na, K, Rb, Cs) were carried out. For describing the Gibbs free energy of liquid ph...By using CALPHAD (Calculation of Phase Diagram) technique the optimization and calculation of the binary systems of TbCl_3-ACl (A= Li, Na, K, Rb, Cs) were carried out. For describing the Gibbs free energy of liquid phase in these systems the new modified quasichemical model in the pair-approximation for short-range ordering was used. From measured phase equilibria data and experimental integral properties the TbCl_3-ACl phase diagrams were optimized and calculated. A set of thermodynamic functions was optimized based on an interactive computer-assisted analysis. The calculated phase diagrams and thermodynamic data are self-consistent.展开更多
Ceria-yttria co-doped zirconia-based multi-components ceramics, with superfine alumina dispersed in the matrix, possess excellent fracture toughness, strength and thermal stability. However, the mechanical properties ...Ceria-yttria co-doped zirconia-based multi-components ceramics, with superfine alumina dispersed in the matrix, possess excellent fracture toughness, strength and thermal stability. However, the mechanical properties and microstructure are strongly dependent on the composition and the fabrication procedure, especially the composition of zirconia containing multi-component ceramics.展开更多
In order to develop the Mg-Zn-Ag metallic glasses(MGs)for biodegradable implant applications,the glass formation ability(GFA)and biocompatibility of Mg-Zn-Ag alloys were investigated using a combination of the calcula...In order to develop the Mg-Zn-Ag metallic glasses(MGs)for biodegradable implant applications,the glass formation ability(GFA)and biocompatibility of Mg-Zn-Ag alloys were investigated using a combination of the calculation of phase diagrams(CALPHAD)and experimental measurements.High GFA potentiality of two alloy series,specifically Mg_(96-x)Zn_xAg_(4)and Mg_(94-x)Zn_xAg_6(x=17,20,23,26,29,32,35),was predicted theoretically and then substantiated through experimental testing.X-ray diffraction(XRD)and differential scanning calorimetry(DSC)techniques were used to evaluate the crystallinity,GFA,and crystallization characteristics of these alloys.The results showed that compositions between Mg_(73)Zn_(23)Ag_(4)and Mg_(64)Zn_(32)Ag_(4)for Mg_(96-x)Zn_xAg_4,Mg_(66)Zn_(28)Ag_(6)and Mg_(63)Zn_(31)Ag_(6for)Mg_(94-x)Zn_xAg_(6)displayed a superior GFA.Notably,the GFA of the Mg_(96-x)Zn_xAg_(4)series was better than that of the Mg_(94-x)Zn_xAg_(6)series.Furthermore,the Mg_(70)Zn_(26)Ag_4,Mg_(74)Zn_(20)Ag_6,and Mg_(71)Zn_(23)Ag_(6)alloys showed acceptable corrosion rates,good cytocompatibility,and positive effects on cell proliferation.These characteristics make them suitable for applications in medical settings,potentially materials as biodegradable implants.展开更多
Based on thermodynamic equilibrium theory,a chemical equilibrium model for GaN g rowth is given in electron cyclotron resonance plasma enhanced metalorganic chem ical vapor deposition (ECR-PEMOCVD) system.Calculation ...Based on thermodynamic equilibrium theory,a chemical equilibrium model for GaN g rowth is given in electron cyclotron resonance plasma enhanced metalorganic chem ical vapor deposition (ECR-PEMOCVD) system.Calculation indicates that the growt h driving force are functions of growth conditions:group Ⅲ input partial press ure,input Ⅴ/Ⅲ ratio,and growth temperature.Furthermore,the growth phase diag rams of hexagonal and cubic GaN film growth are obtained,which are consistent wi th our experimental conditions to some extent.Through analysis,it is explained t he reason that high temperature and high input Ⅴ/Ⅲ ratio are favorable for he xagonal GaN film growth.This model can be extended to the similar systems used f or GaN single-crystal film growth.展开更多
Recent progress on research activities of phase diagrams in our laboratory has been presented. Experimental studies and thermodynamic calculations based on CALPHAD (Calculation of Phase Diagrams) method have been cond...Recent progress on research activities of phase diagrams in our laboratory has been presented. Experimental studies and thermodynamic calculations based on CALPHAD (Calculation of Phase Diagrams) method have been conducted in the following alloy systems.1.Database on microalloying steels including carbide, nitride and sulfide is now being constructed.2.ADAMIS (Alloy Database for Micro-Solders) containing 8 elements of Ag, Bi, Cu,In, Sb, Sn, Zn and Pb has been constructed, which can handle all combinations of these elements and all composition ranges.3.A thermodynamic database of Cu-base alloys including Cu-X binary system and Cu-Fe, Cu-Ni, Cu-Cr base ternary systems has been constructed.4.Experimental and thermodynamic calculations on Fe, Ni, Co and Ti aluminides have been conducted.5.Experimental and thermodynamic calculations on Co base magnetic recording media have been conducted.6.Thermodynamic analysis of interaction between magnetic and chemical orderings has been performed.By utilizing the information on phase diagrams, the following advanced materials have been developed. (A)New type of high speed steel with high hardness about Hv≈1000 by carbide dispersion carburizing method. (B)New Pb-free machinable stainless steel using titanium carbosulphide. (C)New Pb-free solder for Die-attaching use. (D)Shape memory alloys; Cu-base, Ferromagnetic Ni-base and Fe-base. (E)Invar alloys. (F)Egg-type powder.Typical examples of phase diagrams, phase stability, database and its application for the development of advanced materials will be presented.展开更多
Based on the assessment and optimization of nine experimental sub-binary phase diagramsand thermodynamic data (RECl3-LiCl, RECl3-CaCl2 and CaCl2-LiCl), four phase diagrams of theRECl3-CaCl2-LiCl systems are calculated...Based on the assessment and optimization of nine experimental sub-binary phase diagramsand thermodynamic data (RECl3-LiCl, RECl3-CaCl2 and CaCl2-LiCl), four phase diagrams of theRECl3-CaCl2-LiCl systems are calculated and brieflly discussed.展开更多
In-situ refractory metal intermetallic composites(RMICs) based either on (Nb, Si) or (Mo, Si, B) are candidate materials for ultra-high temperature applications (>1400 ℃). To provide a balance of mechanical and en...In-situ refractory metal intermetallic composites(RMICs) based either on (Nb, Si) or (Mo, Si, B) are candidate materials for ultra-high temperature applications (>1400 ℃). To provide a balance of mechanical and environmental properties, Nb-Si composites are typically alloyed with Ti and Cr, and Mo-Si-B composites are alloyed with Ti. Phase diagrams of Nb-Cr-Ti-Si and Mo-Si-B-Ti, as prerequisite knowledge for advanced materials design and processing development, are critically needed. The phase diagrams in the metal-rich regions of multicomponent Nb-Cr-Ti-Si and Mo-Si-B-Ti were rapidly established using the Calphad (Calculation of phase diagram) approach coupled with key experiments. The calculated isotherms, isopleths, and solidification paths were validated by experimental work. The important heterogeneous multiphase equilibria in both quaternary systems identified will offer engineers the opportunity to develop materials with a balance of properties for high-temperature applications.展开更多
In this paper, the interaction parameters in the subregular solution model, λ1 and λ2, are regarded as a linear function of temperature, T. Therefore, the molar excess Gibbs energy of A-B binary system may be reexpr...In this paper, the interaction parameters in the subregular solution model, λ1 and λ2, are regarded as a linear function of temperature, T. Therefore, the molar excess Gibbs energy of A-B binary system may be reexpressed as follows:Gm^E=xAxB[(λ11+λ12T)+(λ21+λ22T)xB]The calculation of the model parameters, λ11, λ12, λ21and λ22, was carried out numerically from the phase diagrams for 11 alkali metal-alkali halide or alkali earth metal-halide systems. In addition, artificial neural network trained by known data has been used to predict the values of these model parameters. The predicted results are in good agreement with the .calculated ones. The applicability of the subregular solution model to the alkali metal-alkali halide or alkali earth metal-halide systems were tested by comparing the available experimental composition along the boundary of miscibility gap with the calculated ones which were obtained by using genetic algorithm. The good agreement between the calculated and experimental results across the entire liquidus is valid evidence in support of the model.展开更多
The thermodynamic calculation of phase equilibria in the Cu-Ni-Si alloy system was carried out using the CALPHAD method. The calculations show that there are three two-phase areas and two three-phase areas in the Cu-r...The thermodynamic calculation of phase equilibria in the Cu-Ni-Si alloy system was carried out using the CALPHAD method. The calculations show that there are three two-phase areas and two three-phase areas in the Cu-rich parts of the isothermal section of the phase diagram at 300-600 ℃,and the three two-phase areas are FCC-A1(Cu-rich)+γ-Ni5Si2,FCC-A1(Cu-rich)+δ-Ni2Si and FCC-A1(Cu-rich)+ε-Ni3Si2,two three-phase areas are FCC-A1(Cu-rich)+γ-Ni5Si2+δ-Ni2Si and FCC-A1(Cu-rich)+δ-Ni2Si+ε-Ni3Si2. For this reason,an alloy located in the Cu-rich portion may precipitate γ-Ni5Si2,δ-Ni2Si or ε-Ni3Si2;the proportion of each phase depends on the alloy composition and aging temperature. The transmission electron microscope analysis of the Cu-3.2Ni-0.75Si alloy indicates that the precipitates are mainly δ-Ni2Si with only a few γ-Ni5Si2 phase particles,which agrees well with the thermodynamic calculations of phase equilibria.展开更多
Phase equilibria including γ,γ′,η,β and H in Ni Al Ti system were investigated by diffusion couple method and calculated with thermodynamic model.The experimental phase equilibria generally agree with ones ...Phase equilibria including γ,γ′,η,β and H in Ni Al Ti system were investigated by diffusion couple method and calculated with thermodynamic model.The experimental phase equilibria generally agree with ones reported till now.Regular solution and sublattice models were used in order to calculate these phase equilibria.The calculated results show agreement with experimental data.展开更多
Numerical methods commonly used for the calculating phase diagrams were listed. A new method to calculate stable phase diagrams was presented which possesse the advantages of both the New-ton Raphson method and the si...Numerical methods commonly used for the calculating phase diagrams were listed. A new method to calculate stable phase diagrams was presented which possesse the advantages of both the New-ton Raphson method and the simplex method. This method is suitable for the calculation of the stable equilibria in complicated systems. For example. calculated results in comparison with experimental results as well as the prediction of new systems were shown in the present work展开更多
Experimental and theoretical studies of the mechanisms of vibration stimulation of oil recovery in watered fields lead to the conclusion that resonance oscillations develop in fractured-block formations. These oscilla...Experimental and theoretical studies of the mechanisms of vibration stimulation of oil recovery in watered fields lead to the conclusion that resonance oscillations develop in fractured-block formations. These oscillations, caused by weak but long-lasting and frequency-stable influences, create the conditions for ultrasonic wave’s generation in the layers, which are capable of destroying thickened oil membranes in reservoir cracks. For fractured-porous reservoirs in the process of exploitation by the method of water high-pressure oil displacement, the possibility of intensifying ultrasonic vibrations can have an important technological significance. Even a very weak ultrasound can destroy, over a long period of time, the viscous oil membranes formed in the cracks between the blocks, which can be the reason for lowering the permeability of the layers and increasing the oil recovery. To describe these effects, it is necessary to consider the wave process in a hierarchically blocky environment and theoretically simulate the mechanism of the appearance of self-oscillations under the action of relaxation shear stresses. For the analysis of seism acoustic response in time on fixed intervals along the borehole an algorithm of phase diagrams of the state of many-phase medium is suggested.展开更多
The high-pressure diagram of V–N compounds is enriched by proposed seven new stable high-pressure phases.The P-1-VN_4with the armchair N-rich structure may be quenched to ambient conditions.The formed N–N covalent b...The high-pressure diagram of V–N compounds is enriched by proposed seven new stable high-pressure phases.The P-1-VN_4with the armchair N-rich structure may be quenched to ambient conditions.The formed N–N covalent bond plays an important role for the structural stability of N-chain.The charge transfer results in a V–N ionic bond interaction,which further improves the stability of N-chain structure.The P-1-VN_4,P4mnc-VN_8,and Immm-VN_(10)with the outstanding detonation properties have potential application in explosive field.展开更多
基金supported by the National Key R&D Program of China(Grant No.2023YFA1406200).
文摘Cubic boron nitride and hexagonal boron nitride are the two predominant crystalline structures of boron nitride.They can interconvert under varying pressure and temperature conditions.However,this transformation requires overcoming significant potential barriers in dynamics,which poses great difficulty in determining the c-BN/h-BN phase boundary.This study used high-pressure in situ differential thermal measurements to ascertain the temperature of h-BN/c-BN conversion within the commonly used pressure range(3-6 GPa)for the industrial synthesis of c-BN to constrain the P-T phase boundary of h-BN/c-BN in the pressure-temperature range as much as possible.Based on the analysis of the experimental data,it is determined that the relationship between pressure and temperature conforms to the following equation:P=a+1/bT.Here,P denotes the pressure(GPa)and T is the temperature(K).The coefficients are a=-3.8±0.8 GPa and b=229.8±17.1 GPa/K.These findings call into question existing high-pressure and high-temperature phase diagrams of boron nitride,which seem to overstate the phase boundary temperature between c-BN and h-BN.The BN phase diagram obtained from this study can provide critical temperature and pressure condition guidance for the industrial synthesis of c-BN,thus optimizing synthesis efficiency and product performance.
基金Projects supported by the National Natural Science Foundation of China (59434080) Foundation of Natural Science of AnhuiProvince (00046509)+1 种基金 Foundation of Natural Science of Anhui Education Committee (2000j1090) and Youth Foundation of Anhui Normal
文摘By using CALPHAD (Calculation of Phase Diagram) technique the optimization and calculation of the binary systems of TbCl_3-ACl (A= Li, Na, K, Rb, Cs) were carried out. For describing the Gibbs free energy of liquid phase in these systems the new modified quasichemical model in the pair-approximation for short-range ordering was used. From measured phase equilibria data and experimental integral properties the TbCl_3-ACl phase diagrams were optimized and calculated. A set of thermodynamic functions was optimized based on an interactive computer-assisted analysis. The calculated phase diagrams and thermodynamic data are self-consistent.
文摘Ceria-yttria co-doped zirconia-based multi-components ceramics, with superfine alumina dispersed in the matrix, possess excellent fracture toughness, strength and thermal stability. However, the mechanical properties and microstructure are strongly dependent on the composition and the fabrication procedure, especially the composition of zirconia containing multi-component ceramics.
基金the financial supports from the Shenzhen Basic Research Project,China(No.JCYJ20170815153210359)the National Natural Science Foundation of China(No.12174210)。
文摘In order to develop the Mg-Zn-Ag metallic glasses(MGs)for biodegradable implant applications,the glass formation ability(GFA)and biocompatibility of Mg-Zn-Ag alloys were investigated using a combination of the calculation of phase diagrams(CALPHAD)and experimental measurements.High GFA potentiality of two alloy series,specifically Mg_(96-x)Zn_xAg_(4)and Mg_(94-x)Zn_xAg_6(x=17,20,23,26,29,32,35),was predicted theoretically and then substantiated through experimental testing.X-ray diffraction(XRD)and differential scanning calorimetry(DSC)techniques were used to evaluate the crystallinity,GFA,and crystallization characteristics of these alloys.The results showed that compositions between Mg_(73)Zn_(23)Ag_(4)and Mg_(64)Zn_(32)Ag_(4)for Mg_(96-x)Zn_xAg_4,Mg_(66)Zn_(28)Ag_(6)and Mg_(63)Zn_(31)Ag_(6for)Mg_(94-x)Zn_xAg_(6)displayed a superior GFA.Notably,the GFA of the Mg_(96-x)Zn_xAg_(4)series was better than that of the Mg_(94-x)Zn_xAg_(6)series.Furthermore,the Mg_(70)Zn_(26)Ag_4,Mg_(74)Zn_(20)Ag_6,and Mg_(71)Zn_(23)Ag_(6)alloys showed acceptable corrosion rates,good cytocompatibility,and positive effects on cell proliferation.These characteristics make them suitable for applications in medical settings,potentially materials as biodegradable implants.
文摘Based on thermodynamic equilibrium theory,a chemical equilibrium model for GaN g rowth is given in electron cyclotron resonance plasma enhanced metalorganic chem ical vapor deposition (ECR-PEMOCVD) system.Calculation indicates that the growt h driving force are functions of growth conditions:group Ⅲ input partial press ure,input Ⅴ/Ⅲ ratio,and growth temperature.Furthermore,the growth phase diag rams of hexagonal and cubic GaN film growth are obtained,which are consistent wi th our experimental conditions to some extent.Through analysis,it is explained t he reason that high temperature and high input Ⅴ/Ⅲ ratio are favorable for he xagonal GaN film growth.This model can be extended to the similar systems used f or GaN single-crystal film growth.
文摘Recent progress on research activities of phase diagrams in our laboratory has been presented. Experimental studies and thermodynamic calculations based on CALPHAD (Calculation of Phase Diagrams) method have been conducted in the following alloy systems.1.Database on microalloying steels including carbide, nitride and sulfide is now being constructed.2.ADAMIS (Alloy Database for Micro-Solders) containing 8 elements of Ag, Bi, Cu,In, Sb, Sn, Zn and Pb has been constructed, which can handle all combinations of these elements and all composition ranges.3.A thermodynamic database of Cu-base alloys including Cu-X binary system and Cu-Fe, Cu-Ni, Cu-Cr base ternary systems has been constructed.4.Experimental and thermodynamic calculations on Fe, Ni, Co and Ti aluminides have been conducted.5.Experimental and thermodynamic calculations on Co base magnetic recording media have been conducted.6.Thermodynamic analysis of interaction between magnetic and chemical orderings has been performed.By utilizing the information on phase diagrams, the following advanced materials have been developed. (A)New type of high speed steel with high hardness about Hv≈1000 by carbide dispersion carburizing method. (B)New Pb-free machinable stainless steel using titanium carbosulphide. (C)New Pb-free solder for Die-attaching use. (D)Shape memory alloys; Cu-base, Ferromagnetic Ni-base and Fe-base. (E)Invar alloys. (F)Egg-type powder.Typical examples of phase diagrams, phase stability, database and its application for the development of advanced materials will be presented.
文摘Based on the assessment and optimization of nine experimental sub-binary phase diagramsand thermodynamic data (RECl3-LiCl, RECl3-CaCl2 and CaCl2-LiCl), four phase diagrams of theRECl3-CaCl2-LiCl systems are calculated and brieflly discussed.
文摘In-situ refractory metal intermetallic composites(RMICs) based either on (Nb, Si) or (Mo, Si, B) are candidate materials for ultra-high temperature applications (>1400 ℃). To provide a balance of mechanical and environmental properties, Nb-Si composites are typically alloyed with Ti and Cr, and Mo-Si-B composites are alloyed with Ti. Phase diagrams of Nb-Cr-Ti-Si and Mo-Si-B-Ti, as prerequisite knowledge for advanced materials design and processing development, are critically needed. The phase diagrams in the metal-rich regions of multicomponent Nb-Cr-Ti-Si and Mo-Si-B-Ti were rapidly established using the Calphad (Calculation of phase diagram) approach coupled with key experiments. The calculated isotherms, isopleths, and solidification paths were validated by experimental work. The important heterogeneous multiphase equilibria in both quaternary systems identified will offer engineers the opportunity to develop materials with a balance of properties for high-temperature applications.
文摘In this paper, the interaction parameters in the subregular solution model, λ1 and λ2, are regarded as a linear function of temperature, T. Therefore, the molar excess Gibbs energy of A-B binary system may be reexpressed as follows:Gm^E=xAxB[(λ11+λ12T)+(λ21+λ22T)xB]The calculation of the model parameters, λ11, λ12, λ21and λ22, was carried out numerically from the phase diagrams for 11 alkali metal-alkali halide or alkali earth metal-halide systems. In addition, artificial neural network trained by known data has been used to predict the values of these model parameters. The predicted results are in good agreement with the .calculated ones. The applicability of the subregular solution model to the alkali metal-alkali halide or alkali earth metal-halide systems were tested by comparing the available experimental composition along the boundary of miscibility gap with the calculated ones which were obtained by using genetic algorithm. The good agreement between the calculated and experimental results across the entire liquidus is valid evidence in support of the model.
基金Project(2006DFB53050) supported by the International Science and Technology Cooperation Project of the Science and Technology Ministry of China
文摘The thermodynamic calculation of phase equilibria in the Cu-Ni-Si alloy system was carried out using the CALPHAD method. The calculations show that there are three two-phase areas and two three-phase areas in the Cu-rich parts of the isothermal section of the phase diagram at 300-600 ℃,and the three two-phase areas are FCC-A1(Cu-rich)+γ-Ni5Si2,FCC-A1(Cu-rich)+δ-Ni2Si and FCC-A1(Cu-rich)+ε-Ni3Si2,two three-phase areas are FCC-A1(Cu-rich)+γ-Ni5Si2+δ-Ni2Si and FCC-A1(Cu-rich)+δ-Ni2Si+ε-Ni3Si2. For this reason,an alloy located in the Cu-rich portion may precipitate γ-Ni5Si2,δ-Ni2Si or ε-Ni3Si2;the proportion of each phase depends on the alloy composition and aging temperature. The transmission electron microscope analysis of the Cu-3.2Ni-0.75Si alloy indicates that the precipitates are mainly δ-Ni2Si with only a few γ-Ni5Si2 phase particles,which agrees well with the thermodynamic calculations of phase equilibria.
文摘Phase equilibria including γ,γ′,η,β and H in Ni Al Ti system were investigated by diffusion couple method and calculated with thermodynamic model.The experimental phase equilibria generally agree with ones reported till now.Regular solution and sublattice models were used in order to calculate these phase equilibria.The calculated results show agreement with experimental data.
文摘Numerical methods commonly used for the calculating phase diagrams were listed. A new method to calculate stable phase diagrams was presented which possesse the advantages of both the New-ton Raphson method and the simplex method. This method is suitable for the calculation of the stable equilibria in complicated systems. For example. calculated results in comparison with experimental results as well as the prediction of new systems were shown in the present work
文摘Experimental and theoretical studies of the mechanisms of vibration stimulation of oil recovery in watered fields lead to the conclusion that resonance oscillations develop in fractured-block formations. These oscillations, caused by weak but long-lasting and frequency-stable influences, create the conditions for ultrasonic wave’s generation in the layers, which are capable of destroying thickened oil membranes in reservoir cracks. For fractured-porous reservoirs in the process of exploitation by the method of water high-pressure oil displacement, the possibility of intensifying ultrasonic vibrations can have an important technological significance. Even a very weak ultrasound can destroy, over a long period of time, the viscous oil membranes formed in the cracks between the blocks, which can be the reason for lowering the permeability of the layers and increasing the oil recovery. To describe these effects, it is necessary to consider the wave process in a hierarchically blocky environment and theoretically simulate the mechanism of the appearance of self-oscillations under the action of relaxation shear stresses. For the analysis of seism acoustic response in time on fixed intervals along the borehole an algorithm of phase diagrams of the state of many-phase medium is suggested.
基金Project （59974011） supported by the National Natural Science Foundation of China.Acknowledgements The authors are grateful for financial support from the National Natural Science Foundation of China （59974011）. Heartfelt thanks are also given to the CompuTherm LLC group of Wisconsin-Madison University for providing the software program to calculate the phase equilibria.
文摘The high-pressure diagram of V–N compounds is enriched by proposed seven new stable high-pressure phases.The P-1-VN_4with the armchair N-rich structure may be quenched to ambient conditions.The formed N–N covalent bond plays an important role for the structural stability of N-chain.The charge transfer results in a V–N ionic bond interaction,which further improves the stability of N-chain structure.The P-1-VN_4,P4mnc-VN_8,and Immm-VN_(10)with the outstanding detonation properties have potential application in explosive field.
