Pressure allows the precise tuning of a fundamental parameter, the interatomic distance, which controls the electronic structure and virtually all interatomic interactions that determine material properties. Hence, pr...Pressure allows the precise tuning of a fundamental parameter, the interatomic distance, which controls the electronic structure and virtually all interatomic interactions that determine material properties. Hence, pressure tuning is an effective tool in the search for new materials with enhanced properties. To realize pressure tuning on matter, large-volume press (LVP) apparatuses have been widely used not only to synthesize novel materials but also to implement the in situ measurement of physical properties. Herein, we introduce the LVP apparatuses, including belt-type, cubic anvil, and 6-8 type multi-anvil, that will be constructed at the Synergetic Extreme Condition User Facility (SECUF) at Jilin University. Typically, cell volumes of 1000 mm3 can be obtained at 20 GPa in a belt-type apparatus that is significantly larger than that obtained in a 6-8 type multi-anvil apparatus at the same pressure. Furthermore, the in situ measurement of physical prop- erties, including thermological, electrical, and mechanical behaviors, is coupled to these LVP apparatuses. Some typical results of both synthetic experiments and in situ measurements obtained from the LVP apparatuses are also reviewed.展开更多
In recent years,transition metal borides(TMBs)have attracted much attention because they are considered as potential superhard materials and have more abundant crystal structures compared with traditional superhard ma...In recent years,transition metal borides(TMBs)have attracted much attention because they are considered as potential superhard materials and have more abundant crystal structures compared with traditional superhard materials.So far,however,no superhard materials have been found in TMBs.A large number of structures and potential new properties in TMBs are induced by the various hybridization ways of boron atoms and the high valence electrons of transition metals,which provide many possibilities for its application.And most TMBs have layered structures,which make TMBs have the potential to be a two-dimensional(2D)material.The 2D materials have novel properties,but the research on 2D TMBs is still nearly blank.In this paper,the research progress of TMBs is summarized involving structure,mechanical properties,and multifunctional properties.The strong covalent bonds of boron atoms in TMBs can form one-dimensional,twodimensional,and three-dimensional substructures,and the multiple electron transfer between transition metal and boron leads to a variety of chemical bonds in TMBs,which are the keys to obtain high hardness and multifunctional properties of TMBs.Further research on the multifunctional properties of TMBs,such as superconductors,catalysts,and high hardness ferromagnetic materials,is of great significance to the discovery of new multifunctional hard materials.展开更多
Twinned substructure in lath martensite was induced in the interstitial free(IF)steel via a high pressure thermal cycle(heating up to 1100℃and holding for 30 min,cooling at 10℃/s to room temperature under a pressure...Twinned substructure in lath martensite was induced in the interstitial free(IF)steel via a high pressure thermal cycle(heating up to 1100℃and holding for 30 min,cooling at 10℃/s to room temperature under a pressure of 4 GPa).Experimental observations and theoretical simulation confrm that the twinned substructure has the origin related to the twinned variants rather than the bcc{112}<111>twins,while extra difraction spots were caused by crystal overlapping rather than any extra phase.The diferences in crystallography and electron difraction behavior between twinned variants and{112}<111>twins were discussed in detail.展开更多
Polycrystalline diamond compacts(PDC), which are composed of diamond and WC/Co substrate, and synthesized at high pressure and high temperature(HPHT), are widely applied as the tooth of drilling bit. However, the ...Polycrystalline diamond compacts(PDC), which are composed of diamond and WC/Co substrate, and synthesized at high pressure and high temperature(HPHT), are widely applied as the tooth of drilling bit. However, the thermal stability of PDC will be reduced when diamond transforms into graphite due to cobalt in PDC acting as a catalyst during the drilling work. In this study, a new three-layer structured PDC with enhanced thermal stability has been successfully synthesized at pressures of 5.5–7.0 GPa and temperatures of 1650–1750?C. In this structure, the diamond-Si C composite acts as the working layer,and the diamond-Si C-Co composite and WC/Co cements are as the intermediate layer and substrate,respectively. It is found that the initial oxidizing temperature of the three-layered PDC is enhanced up to820?C, which is significantly higher than that(~780?C) of the conventional PDC counterpart.展开更多
A Fe–1.0 wt%C alloy was quenched into water from 1100 ℃,leading to lath martensite and plate martensite of body-centered tetragonal structure.Both these two martensites have the twinned substructure that generates m...A Fe–1.0 wt%C alloy was quenched into water from 1100 ℃,leading to lath martensite and plate martensite of body-centered tetragonal structure.Both these two martensites have the twinned substructure that generates mirror symmetric diff raction patterns with extra diff raction spots around n/3(112).The twinned substructure has the origin from twinned martensitic variants,namely twin-related crystals separated by{110},rather than{112}<111>deformation twins.Tetragonality eff ect on the electron double diff raction of twinned variants was discussed.展开更多
文摘Pressure allows the precise tuning of a fundamental parameter, the interatomic distance, which controls the electronic structure and virtually all interatomic interactions that determine material properties. Hence, pressure tuning is an effective tool in the search for new materials with enhanced properties. To realize pressure tuning on matter, large-volume press (LVP) apparatuses have been widely used not only to synthesize novel materials but also to implement the in situ measurement of physical properties. Herein, we introduce the LVP apparatuses, including belt-type, cubic anvil, and 6-8 type multi-anvil, that will be constructed at the Synergetic Extreme Condition User Facility (SECUF) at Jilin University. Typically, cell volumes of 1000 mm3 can be obtained at 20 GPa in a belt-type apparatus that is significantly larger than that obtained in a 6-8 type multi-anvil apparatus at the same pressure. Furthermore, the in situ measurement of physical prop- erties, including thermological, electrical, and mechanical behaviors, is coupled to these LVP apparatuses. Some typical results of both synthetic experiments and in situ measurements obtained from the LVP apparatuses are also reviewed.
基金supported by the National Key Research and Development Program of China(Grant Nos.2016YFA0401503 and 2018YFA0305700)the National Natural Science Foundation of China(Grant No.11575288)+1 种基金the Strategic Priority Research Program and Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(Grant Nos.XDB33000000,XDB25000000,and QYZDBSSW-SLH013)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.Y202003)。
文摘In recent years,transition metal borides(TMBs)have attracted much attention because they are considered as potential superhard materials and have more abundant crystal structures compared with traditional superhard materials.So far,however,no superhard materials have been found in TMBs.A large number of structures and potential new properties in TMBs are induced by the various hybridization ways of boron atoms and the high valence electrons of transition metals,which provide many possibilities for its application.And most TMBs have layered structures,which make TMBs have the potential to be a two-dimensional(2D)material.The 2D materials have novel properties,but the research on 2D TMBs is still nearly blank.In this paper,the research progress of TMBs is summarized involving structure,mechanical properties,and multifunctional properties.The strong covalent bonds of boron atoms in TMBs can form one-dimensional,twodimensional,and three-dimensional substructures,and the multiple electron transfer between transition metal and boron leads to a variety of chemical bonds in TMBs,which are the keys to obtain high hardness and multifunctional properties of TMBs.Further research on the multifunctional properties of TMBs,such as superconductors,catalysts,and high hardness ferromagnetic materials,is of great significance to the discovery of new multifunctional hard materials.
基金supported by the Natural Science Foundation-Steel and Iron Foundation of Hebei Province(No.E2021203051)the Hundred Outstanding Creative Talents Projects in Universities of Hebei Province,China,and the Project Program of Heavy Machinery Collaborative Innovation Center,China.
文摘Twinned substructure in lath martensite was induced in the interstitial free(IF)steel via a high pressure thermal cycle(heating up to 1100℃and holding for 30 min,cooling at 10℃/s to room temperature under a pressure of 4 GPa).Experimental observations and theoretical simulation confrm that the twinned substructure has the origin related to the twinned variants rather than the bcc{112}<111>twins,while extra difraction spots were caused by crystal overlapping rather than any extra phase.The diferences in crystallography and electron difraction behavior between twinned variants and{112}<111>twins were discussed in detail.
基金financial supports from the National Natural Science Foundation of China (No. 41572357)
文摘Polycrystalline diamond compacts(PDC), which are composed of diamond and WC/Co substrate, and synthesized at high pressure and high temperature(HPHT), are widely applied as the tooth of drilling bit. However, the thermal stability of PDC will be reduced when diamond transforms into graphite due to cobalt in PDC acting as a catalyst during the drilling work. In this study, a new three-layer structured PDC with enhanced thermal stability has been successfully synthesized at pressures of 5.5–7.0 GPa and temperatures of 1650–1750?C. In this structure, the diamond-Si C composite acts as the working layer,and the diamond-Si C-Co composite and WC/Co cements are as the intermediate layer and substrate,respectively. It is found that the initial oxidizing temperature of the three-layered PDC is enhanced up to820?C, which is significantly higher than that(~780?C) of the conventional PDC counterpart.
基金financially supported by the Hundred Outstanding Creative Talents Projects in Hebei University(SLRC2017058)the Natural Science Foundation—Steel and Iron Foundation of Hebei Province(E2021203051)+1 种基金the Project Program of Heavy Machinery Collaborative Innovation Centerthe National Natural Science Foundation(51171182)。
文摘A Fe–1.0 wt%C alloy was quenched into water from 1100 ℃,leading to lath martensite and plate martensite of body-centered tetragonal structure.Both these two martensites have the twinned substructure that generates mirror symmetric diff raction patterns with extra diff raction spots around n/3(112).The twinned substructure has the origin from twinned martensitic variants,namely twin-related crystals separated by{110},rather than{112}<111>deformation twins.Tetragonality eff ect on the electron double diff raction of twinned variants was discussed.