The microstructure and phase relationship of (Dy0.65Tb0.25Pr0.1)Fex alloys in the composition range of 1.6≤x≤2.1 were investigated using optical microscopy, X-ray diffraction , DTA and EPMA techniques. The variatio...The microstructure and phase relationship of (Dy0.65Tb0.25Pr0.1)Fex alloys in the composition range of 1.6≤x≤2.1 were investigated using optical microscopy, X-ray diffraction , DTA and EPMA techniques. The variations of microstructure and lattice parameter with the iron content,the effect of heat treatment on the microstructure and the phase relationship have been studied.The phase relationship in the vicinity of the Laves phase is proposed展开更多
Our recent studies of the crystal structures, phase transitions, and magnetic properties of intermetallic compounds RsM4 （R = rare earths; M = Si, Ge） are reviewed briefly. First, crystal structures, phase relations...Our recent studies of the crystal structures, phase transitions, and magnetic properties of intermetallic compounds RsM4 （R = rare earths; M = Si, Ge） are reviewed briefly. First, crystal structures, phase relationships, and magnetic prop- erties of several 5：4 compounds, including Nd5 Si4-xGex, Pr5 Si4_xGex, Gds-xLaxGe4, La5 Si4, and Gd5 Sn4, are presented. In particular, the canted spin structures as well as the magnetic phase transitions in PrsSi2Ge2 and PrsGe4 investigated by neutron powder diffractions and small-angle neutron scattering are reviewed. Second, the crystal structures and magnetic properties of the most studied compounds Gds（Si,Ge）4 are summarized. The focus is on the parent compound GdsGe4, which is an amazing material exhibiting magnetic anisotropy, angular dependent spin-flop transition, metastable magnetic response, Griffiths-like phase, thermal effect under pulsed fields, antiferromagnetic and ferromagnetic resonances, pro- nounced effects of impurities, and high-field induced magnetic transitions.展开更多
The phase relationships of R-Fe pseudobinary system(R=Dy0.65Tb0.25Pr0.1) have been determined using optical microscopy,X-ray diffraction,EPMA and DTA techniques.This system contains one eutectic reaction and four peri...The phase relationships of R-Fe pseudobinary system(R=Dy0.65Tb0.25Pr0.1) have been determined using optical microscopy,X-ray diffraction,EPMA and DTA techniques.This system contains one eutectic reaction and four peritectic reactions.The four intermetallic compounds are(Dy,Tb,Pr)Fe2,(Dy,Tb,Pr)Fe3,(Dy,Tb,Pr)6Fe23 and(Dy,Tb,Pr) 2Fe17 The homogeneity regions of these compounds shift towards rare earth-rich side of the stoichiometric composition except(Dy, Tb,Pr) 2Fe17.展开更多
The melting behavior,solid state phase transformation and structure of pseudo-ternary compounds Nd_2(Fe_(1-x)Ni_x)_(14)B and Pr_2(Co_(1-y)Ni_y)_(14)B were studied using differential thermal analysis,optical microscopy...The melting behavior,solid state phase transformation and structure of pseudo-ternary compounds Nd_2(Fe_(1-x)Ni_x)_(14)B and Pr_2(Co_(1-y)Ni_y)_(14)B were studied using differential thermal analysis,optical microscopy X-ray diffraction,and electron probe micro-analysis techniques.At high temperature,eutectoid decomposition R_2(Ni,M)_(17)→R(Ni,M)_5+x-Ni(M) takes place in these two pseudo-ternary compounds,in the composition range x=0.6～1.0 and y=0.3～1.0,respectively.When x(or y)≤0.2,both Nd_2(Fe_(1-x)Ni_x)_(14)B and Pr_2(Co_(1-y)Ni_y)_(14)B are single phase tetragonal.The phase constitutents of these two systems at room tempera- ture are similar in the composition range 0.6≤x(or y)≤1.0.展开更多
Three groups of cylinder specimens(φ10 mm×10 mm)with 20%,30%and 40%(by mass,the same hereinafter)of ZrO2,were prepared using analytically pure MgO,Al2O3 and ZrO2 powders as the starting materials.The specimens w...Three groups of cylinder specimens(φ10 mm×10 mm)with 20%,30%and 40%(by mass,the same hereinafter)of ZrO2,were prepared using analytically pure MgO,Al2O3 and ZrO2 powders as the starting materials.The specimens were fired at 1600℃for 5 h,1700℃for 0 h and 1800℃for 7 h,respectively.The microstructure of the MgO-MgAl2O4-ZrO2 subsystem was studied by FESEM.The results show that(1)in the temperature range of 1600-1700℃,solid phase reactions happen in the MgO-MgAl2O4-ZrO2 subsystem,leaving three phases:periclase,spinel and ZrO2(solid dissolving with Mg2+)co-existing;spinellization affects the densification;(2)the specimen with 40%ZrO2 fired at 1800℃has heterogeneous melting microstructure;some areas form typical ternary eutectic MgO-MgAl2O4-ZrO2 with composition of MgO 35.2%-37.2%,Al2O324.2%-26.6%,and ZrO237.2%-39.8%.展开更多
This is a paper for the sub-solidus phase relationships in the full system Si_3N_4-A1NAl_2O_3-SiO_2-Y_2O_3-YN. Within this system there exist seventy-six compatibility tetrahedra.
The subsolidus phase relationships in the systems R_2O_3-AlN-Al_2O_3 (R=Ce, Pr, Nd.and Sm) and the isothermal section at 1700℃ of the Nd_2O_3-AlN-Al_2O_3 system have beendetermined. A nitrogen-containing R-β-alumina...The subsolidus phase relationships in the systems R_2O_3-AlN-Al_2O_3 (R=Ce, Pr, Nd.and Sm) and the isothermal section at 1700℃ of the Nd_2O_3-AlN-Al_2O_3 system have beendetermined. A nitrogen-containing R-β-alumina phase RAl_(12)O_(18)N has been identified. Theformation of the β-alumina phase occurring at both the compositions RAl_(12)O_(18)N and R_2O_3·11Al_2O_3 was explored in a series of light rare-earth systems. Single-phase N-containing β-aluminas can be obtained with the compositions RAl_(12)O_(18)N (R=La, Ce, Pr, Nd, Sm, andEu). However, La, Ce, Pr and Eu can also form β-alumina phase as the main phase at thecompositions of R_2O_3·11Al_2O_3, which form continuous solid solutions with RAl_(12)O_(18)N. Theunit cell dimensions of RAl_(12)O_(18)N have been determined to be α=5.557 (A) and c=22.00 (A) and there appears no deviation among the different R-β-aluminas (R=Ce→Sm)that can be detected. At 1700℃, an extensive liquid region exists in the triangle Nd_2O_3-Nd_2AlO_3N-NdAlO_3.展开更多
Ⅰ. INTRODUCTIONMgO was first used as a sintering additive in the fabrication of Si<sub>3</sub>N<sub>4</sub> ceramics. Another common sintering additive Al<sub>2</sub>O<sub>3&...Ⅰ. INTRODUCTIONMgO was first used as a sintering additive in the fabrication of Si<sub>3</sub>N<sub>4</sub> ceramics. Another common sintering additive Al<sub>2</sub>O<sub>3</sub> combined with AIN can be accommodated in β-Si<sub>3</sub>N<sub>4</sub> structure to form β-sialon. A thorough understanding of the effect of those combined additives depends on the knowledge of the phase relationships in the system Mg-Si-Al-O-N.展开更多
Based on the crystal growth system of rhombohedral 2Zn-insulin,the phase transition ofinsulin crystals has been investigated with the phenol concentration as an independent component.The dia-gram of the phase relation...Based on the crystal growth system of rhombohedral 2Zn-insulin,the phase transition ofinsulin crystals has been investigated with the phenol concentration as an independent component.The dia-gram of the phase relationship in this crystal growth system was established,and two points of phase transi-tion were found.The transition point Ⅰ indicates the phase transition between rhombohedral 2Zn-insulin crys-tal and rhombohedral 4Zn-insulin crystal,and these two phases coexist within a narrow region of phenol con-centration (0.028%-0.029% (g/ml)).Point Ⅱ at 0.76%-0.77% (g/ml) of phenol concentration showsthe phase transition between rhombohcdral crystal and monoclinic crystals,and a new phase of monocliniccrystal (B-form monoclinic insulin crystal) has been observed.This paper reports the diagram of phase rela-tionship obtained from our experiments,and analyses and discusses the dependence of phase transition of in-sulin crystals on phenol concentration in crystal growth system.展开更多
The subsolidus phase diagram of Si_3N_4-Y_2O_3-La_2O_3 system has been shown to involve fourtwo-phase regions and eight three-phase triangles. In Si_3N_4-rich area, there exists a new phase,0.4 Y_2O_3·0.6La_2O_3&...The subsolidus phase diagram of Si_3N_4-Y_2O_3-La_2O_3 system has been shown to involve fourtwo-phase regions and eight three-phase triangles. In Si_3N_4-rich area, there exists a new phase,0.4 Y_2O_3·0.6La_2O_3·3Si_3N_4. A limited solid solution of Y_2O_3·Si_3N_4 with La replacing Y up to55 mol% La_2O_3 has been defined. The reverse replacement does not occur. Three continuous solidsolutions of nitrogen-containing silicates in Y-La-Si-O-N system have been confirmed. Theyare J-phase(2(Y,La)_2O_3·Si_2N_2O), K-phase ((Y,La)_2O_3·Si_2N_2O) and H-phase((Y, La)_(10)(SiO_4)_6N_2).展开更多
This study employed proxy data to investigate the phase relationship between the North Atlantic deep-level temperature and the Qinghai-Tibet Plateau(TP)surface air temperature(TP temperature)and its evolution at the m...This study employed proxy data to investigate the phase relationship between the North Atlantic deep-level temperature and the Qinghai-Tibet Plateau(TP)surface air temperature(TP temperature)and its evolution at the millennial scale since the Last Interglaciation.The results indicate the alternation of in-phase and anti-phase relationships since the Last Interglaciation,with the in-phase relationships showing a shorter duration than the anti-phase relationships.Alternations between the in-phase and antiphase relationships occurred more frequently during the Last Interglaciation than during the Last Glaciation.The phase relationship between the North Atlantic deep-level temperature and the TP temperature was broadly illustrated by that between the North Atlantic temperature(based on oxygen isotope data from the Greenland ice core)and TP temperature.Furthermore,the North Atlantic deep-level temperature and the TP temperature may be connected through the North Atlantic sea surface temperature.展开更多
Phase equilibria focusing on the long-period stacking ordered(LPSO)phases have been experimentally in-vestigated in the Mg-Y-Al alloys.The microstructures of the eleven representative alloys annealed at 450,500 and 55...Phase equilibria focusing on the long-period stacking ordered(LPSO)phases have been experimentally in-vestigated in the Mg-Y-Al alloys.The microstructures of the eleven representative alloys annealed at 450,500 and 550°C were systematically investigated using X-ray diffraction(XRD),scanning electron mi-croscopy(SEM)and transmission electron microscopy(TEM).Two thermodynamically stable LPSO poly-types were identified,including 18R and 10H structures.Meanwhile,the transformation of 18R→10H was detected in Mg-9.0Y-1.7Al(at.%)alloy,while the coexistence of 18R and 10H was observed in Mg-14.2Y-12.8Al(at.%)alloy.It was found that the LPSO phases were non-stoichiometric compounds with ternary solubilities.The 18R can dissolve up to 7.21 at.%-8.37 at.%Al and 10.75 at.%-12.01 at.%Y,while the 10H can dissolve up to 9.35 at.%-10.37 at.%Al and 14.50 at.%-14.94 at.%Y.All of the experimental re-sults were used to construct the isothermal sections,which is conducive to the design of Mg-Y-Al alloys.展开更多
Analysis electron microtechnique (AEM) and high resolution electron microtechnique (HREM) studies were conducted on a spray deposition Al 8.5Fe 1.3V 1.7Si(mass fraction, %) alloy to determine the characteristics of th...Analysis electron microtechnique (AEM) and high resolution electron microtechnique (HREM) studies were conducted on a spray deposition Al 8.5Fe 1.3V 1.7Si(mass fraction, %) alloy to determine the characteristics of the intermetallic phases. The results show that the striking characteristics of the microstructures in as deposited and as extruded alloys indicate the presence of a large amounts of homogeneously distributed fine particles and a few coarse particles, while small amount of eutectics consisted of α (Al) and α AlFeSi are found in local zone in as deposited alloy. The fine particle is identified to be bcc α AlFeSi phase, and the coarse particles are monoclinic α Al 13 Fe 4 equilibrium phase, bcc α AlFeSi phase and newly found hexagonal h AlFeSi metastable phase. In α Al 13 Fe 4 , stacking faults on (100) and (001) plane and microtwin on (100) twinning plane are frequently observed. The extra reflection spots in α AlFeSi reflection pattern can be induced by α AlFeSi superstructure. The hexagonal metastable phase transforms to bcc phase, and the compositions of two phases are very similar. A close crystallographic orientation relationship between hexagonal and bcc phases are determined, and HREM image shows that the interface between them is coherent. [展开更多
Copper-manganese-aluminum （CMA） alloys, containing small additions of Fe, Ni, and Si, exhibit good strength and remarkable corrosion resistance against sea water. The alloys are used in as-cast condition, and their ...Copper-manganese-aluminum （CMA） alloys, containing small additions of Fe, Ni, and Si, exhibit good strength and remarkable corrosion resistance against sea water. The alloys are used in as-cast condition, and their microstructure can show wide variations. The morphology, crystallography and composition of the phases presented in an as-cast （CMA） alloy of nominal composition Cu-14%Mn-8%Al-3%Fe-2%Ni were investigated using optical, electron optical, and microprobe analytical techniques. The as-cast microstructure consisted of the grains of fcc α and bcc β-phases alongwith intermetallic precipitates of various morphologies. The room temperature microstructure exhibited four different types of precipitates inside the α-grains： the ＇large＇ dendritic-shaped particles and the cuboid-shaped precipitates, which were rich in Fe and Mn and had an fcc structure, while the ＇small＇ dendritic-shaped particles and the globular precipitates were based on FeaAI and had DO3 structure. These four different morphologies of intermetallic precipitates exhibited discrete orientation-relationships with the α-matrix. The β-grains only contained very small cuboid shaped precipitates, which could only be resolved through transmission electron microscopy. These precipitates were found to be based on Fe3Al and had the DO3 structure.展开更多
The detailed structures and the corresponding formation mechanisms of the well-known Al_(10)RE_2Mn_7 phase in the conventional die-cast Mg–4Al–4RE–0.3Mn alloy were thoroughly investigated using transmission electro...The detailed structures and the corresponding formation mechanisms of the well-known Al_(10)RE_2Mn_7 phase in the conventional die-cast Mg–4Al–4RE–0.3Mn alloy were thoroughly investigated using transmission electron microscopy(TEM). The results indicate that the Al_(10)RE_2Mn_7 phase ordinarily contains both normal (111) twins and orientation twins.Both detailed TEM observations and density functional theory calculations indicate that the Al_(10)RE_2Mn_7 phase is transferred from the Al_8REMn_4 phase following an orientation relationship as [010]_(Al_8REMn_4)//[101]_(Al_(10)RE_2Mn_7) and (101)_(Al_8REMn_4)//(110)_(Al_(10)RE_2Mn_7). Moreover, forming orientation twins in the Al_(10)RE_2Mn_7 phase is attributed to the blurry regions at incoherent twin boundaries in the Al_8REMn_4 phase. Finally, these formed orientation twins result in the (111) twins in the Al_(10)RE_2Mn_7 phase.展开更多
The study of dynamic relationships between the atmospheric carbon dioxide and the Earth’s global temperature in the current changing climate supported the notion that the trend in the global temperature followed the ...The study of dynamic relationships between the atmospheric carbon dioxide and the Earth’s global temperature in the current changing climate supported the notion that the trend in the global temperature followed the trend in the atmospheric CO2 before the climate hiatus that started in the beginning of the 21st century. During the hiatus period, the heat trapped by the atmospheric CO2 is going mostly to the ocean. This conclusion is supported by comparison of the CO2 trend with the trend in the ocean heat content. The phase relationships between the CO2 and temperature are more complicated after the removal of the trends. The phase relationships are chaotic on time scales shorter than the annual time scale. During 1986-2008, the atmospheric CO2 changed in an-ti-phase with the global temperature. The phase relationship reversed in 1979 and after 2010. The atmospheric CO2 was in-phase with the global temperature on the El Nino time scale (2.3 - 7 years) except during very strong El Nino years in 1991-1999 when CO2 led the global temperature.展开更多
T_(1)'phase in Al-2.6Li-1.3Cu alloy was studied systematically by selected area clectron diffraction,serial rotation and matrix analysis of electron diffraction pattern.The results show that the crystalline struct...T_(1)'phase in Al-2.6Li-1.3Cu alloy was studied systematically by selected area clectron diffraction,serial rotation and matrix analysis of electron diffraction pattern.The results show that the crystalline structure of T,’phase is orthohombic.The lattice parameters are a=0.2876nm,b=0.86nm,c=0.406nm,and orientation relationship with the matrix is(010)://(110)。,[001]T_(1)'//[100]。.展开更多
How to improve the probability of registration and precision of localization is a hard problem, which is desiderated to solve. The two basic approaches (normalized cross-correlation and phase correlation) for image re...How to improve the probability of registration and precision of localization is a hard problem, which is desiderated to solve. The two basic approaches (normalized cross-correlation and phase correlation) for image registration are analysed, two improved approaches based on spatial-temporal relationship are presented. This method adds the correlation matrix according to the displacements in x- cirection and y- directions, and the registration pose is searched in the added matrix. The method overcomes the shortcoming that the probability of registration decreasing with area increasing owing to geometric distortion, improves the probability and the robustness of registration.展开更多
文摘The microstructure and phase relationship of (Dy0.65Tb0.25Pr0.1)Fex alloys in the composition range of 1.6≤x≤2.1 were investigated using optical microscopy, X-ray diffraction , DTA and EPMA techniques. The variations of microstructure and lattice parameter with the iron content,the effect of heat treatment on the microstructure and the phase relationship have been studied.The phase relationship in the vicinity of the Laves phase is proposed
基金supported by the National Natural Science Foundation of China (Grants Nos. 50025102 and 50631040)the National Basic Research Program of China (Grant No. 2006CB601101)+1 种基金the Exchange Program between NIST and the Chinese Academy of Sciencesthe Natural Science Foundation of Guangxi Province, China (Grant No. 2012GXNSFGA060002)
文摘Our recent studies of the crystal structures, phase transitions, and magnetic properties of intermetallic compounds RsM4 （R = rare earths; M = Si, Ge） are reviewed briefly. First, crystal structures, phase relationships, and magnetic prop- erties of several 5：4 compounds, including Nd5 Si4-xGex, Pr5 Si4_xGex, Gds-xLaxGe4, La5 Si4, and Gd5 Sn4, are presented. In particular, the canted spin structures as well as the magnetic phase transitions in PrsSi2Ge2 and PrsGe4 investigated by neutron powder diffractions and small-angle neutron scattering are reviewed. Second, the crystal structures and magnetic properties of the most studied compounds Gds（Si,Ge）4 are summarized. The focus is on the parent compound GdsGe4, which is an amazing material exhibiting magnetic anisotropy, angular dependent spin-flop transition, metastable magnetic response, Griffiths-like phase, thermal effect under pulsed fields, antiferromagnetic and ferromagnetic resonances, pro- nounced effects of impurities, and high-field induced magnetic transitions.
文摘The phase relationships of R-Fe pseudobinary system(R=Dy0.65Tb0.25Pr0.1) have been determined using optical microscopy,X-ray diffraction,EPMA and DTA techniques.This system contains one eutectic reaction and four peritectic reactions.The four intermetallic compounds are(Dy,Tb,Pr)Fe2,(Dy,Tb,Pr)Fe3,(Dy,Tb,Pr)6Fe23 and(Dy,Tb,Pr) 2Fe17 The homogeneity regions of these compounds shift towards rare earth-rich side of the stoichiometric composition except(Dy, Tb,Pr) 2Fe17.
基金the National Natural Science Fundation of China.
文摘The melting behavior,solid state phase transformation and structure of pseudo-ternary compounds Nd_2(Fe_(1-x)Ni_x)_(14)B and Pr_2(Co_(1-y)Ni_y)_(14)B were studied using differential thermal analysis,optical microscopy X-ray diffraction,and electron probe micro-analysis techniques.At high temperature,eutectoid decomposition R_2(Ni,M)_(17)→R(Ni,M)_5+x-Ni(M) takes place in these two pseudo-ternary compounds,in the composition range x=0.6～1.0 and y=0.3～1.0,respectively.When x(or y)≤0.2,both Nd_2(Fe_(1-x)Ni_x)_(14)B and Pr_2(Co_(1-y)Ni_y)_(14)B are single phase tetragonal.The phase constitutents of these two systems at room tempera- ture are similar in the composition range 0.6≤x(or y)≤1.0.
基金The author would like to thank Fu Qiuhua,Zhang Wei and Fan Qingsong for their surport to this work.
文摘Three groups of cylinder specimens(φ10 mm×10 mm)with 20%,30%and 40%(by mass,the same hereinafter)of ZrO2,were prepared using analytically pure MgO,Al2O3 and ZrO2 powders as the starting materials.The specimens were fired at 1600℃for 5 h,1700℃for 0 h and 1800℃for 7 h,respectively.The microstructure of the MgO-MgAl2O4-ZrO2 subsystem was studied by FESEM.The results show that(1)in the temperature range of 1600-1700℃,solid phase reactions happen in the MgO-MgAl2O4-ZrO2 subsystem,leaving three phases:periclase,spinel and ZrO2(solid dissolving with Mg2+)co-existing;spinellization affects the densification;(2)the specimen with 40%ZrO2 fired at 1800℃has heterogeneous melting microstructure;some areas form typical ternary eutectic MgO-MgAl2O4-ZrO2 with composition of MgO 35.2%-37.2%,Al2O324.2%-26.6%,and ZrO237.2%-39.8%.
基金Materials Science and Engineering Department, The University of Michigan, U. S. A
文摘This is a paper for the sub-solidus phase relationships in the full system Si_3N_4-A1NAl_2O_3-SiO_2-Y_2O_3-YN. Within this system there exist seventy-six compatibility tetrahedra.
基金Project supported by the National Natural Scieuce Foundation of China.
文摘The subsolidus phase relationships in the systems R_2O_3-AlN-Al_2O_3 (R=Ce, Pr, Nd.and Sm) and the isothermal section at 1700℃ of the Nd_2O_3-AlN-Al_2O_3 system have beendetermined. A nitrogen-containing R-β-alumina phase RAl_(12)O_(18)N has been identified. Theformation of the β-alumina phase occurring at both the compositions RAl_(12)O_(18)N and R_2O_3·11Al_2O_3 was explored in a series of light rare-earth systems. Single-phase N-containing β-aluminas can be obtained with the compositions RAl_(12)O_(18)N (R=La, Ce, Pr, Nd, Sm, andEu). However, La, Ce, Pr and Eu can also form β-alumina phase as the main phase at thecompositions of R_2O_3·11Al_2O_3, which form continuous solid solutions with RAl_(12)O_(18)N. Theunit cell dimensions of RAl_(12)O_(18)N have been determined to be α=5.557 (A) and c=22.00 (A) and there appears no deviation among the different R-β-aluminas (R=Ce→Sm)that can be detected. At 1700℃, an extensive liquid region exists in the triangle Nd_2O_3-Nd_2AlO_3N-NdAlO_3.
文摘Ⅰ. INTRODUCTIONMgO was first used as a sintering additive in the fabrication of Si<sub>3</sub>N<sub>4</sub> ceramics. Another common sintering additive Al<sub>2</sub>O<sub>3</sub> combined with AIN can be accommodated in β-Si<sub>3</sub>N<sub>4</sub> structure to form β-sialon. A thorough understanding of the effect of those combined additives depends on the knowledge of the phase relationships in the system Mg-Si-Al-O-N.
基金the Foundation of Chinese Academy of Sciencesthe National Natural Science Foundation of China
文摘Based on the crystal growth system of rhombohedral 2Zn-insulin,the phase transition ofinsulin crystals has been investigated with the phenol concentration as an independent component.The dia-gram of the phase relationship in this crystal growth system was established,and two points of phase transi-tion were found.The transition point Ⅰ indicates the phase transition between rhombohedral 2Zn-insulin crys-tal and rhombohedral 4Zn-insulin crystal,and these two phases coexist within a narrow region of phenol con-centration (0.028%-0.029% (g/ml)).Point Ⅱ at 0.76%-0.77% (g/ml) of phenol concentration showsthe phase transition between rhombohcdral crystal and monoclinic crystals,and a new phase of monocliniccrystal (B-form monoclinic insulin crystal) has been observed.This paper reports the diagram of phase rela-tionship obtained from our experiments,and analyses and discusses the dependence of phase transition of in-sulin crystals on phenol concentration in crystal growth system.
文摘The subsolidus phase diagram of Si_3N_4-Y_2O_3-La_2O_3 system has been shown to involve fourtwo-phase regions and eight three-phase triangles. In Si_3N_4-rich area, there exists a new phase,0.4 Y_2O_3·0.6La_2O_3·3Si_3N_4. A limited solid solution of Y_2O_3·Si_3N_4 with La replacing Y up to55 mol% La_2O_3 has been defined. The reverse replacement does not occur. Three continuous solidsolutions of nitrogen-containing silicates in Y-La-Si-O-N system have been confirmed. Theyare J-phase(2(Y,La)_2O_3·Si_2N_2O), K-phase ((Y,La)_2O_3·Si_2N_2O) and H-phase((Y, La)_(10)(SiO_4)_6N_2).
基金supported by the Special Foundation for the National Science and Technology Major Project of China(2011FY120300)the National Natural Science Foundation of China(41001058)
文摘This study employed proxy data to investigate the phase relationship between the North Atlantic deep-level temperature and the Qinghai-Tibet Plateau(TP)surface air temperature(TP temperature)and its evolution at the millennial scale since the Last Interglaciation.The results indicate the alternation of in-phase and anti-phase relationships since the Last Interglaciation,with the in-phase relationships showing a shorter duration than the anti-phase relationships.Alternations between the in-phase and antiphase relationships occurred more frequently during the Last Interglaciation than during the Last Glaciation.The phase relationship between the North Atlantic deep-level temperature and the TP temperature was broadly illustrated by that between the North Atlantic temperature(based on oxygen isotope data from the Greenland ice core)and TP temperature.Furthermore,the North Atlantic deep-level temperature and the TP temperature may be connected through the North Atlantic sea surface temperature.
基金supported by the National Natural Science Foun-dation of China(Nos.52001199,51825101).
文摘Phase equilibria focusing on the long-period stacking ordered(LPSO)phases have been experimentally in-vestigated in the Mg-Y-Al alloys.The microstructures of the eleven representative alloys annealed at 450,500 and 550°C were systematically investigated using X-ray diffraction(XRD),scanning electron mi-croscopy(SEM)and transmission electron microscopy(TEM).Two thermodynamically stable LPSO poly-types were identified,including 18R and 10H structures.Meanwhile,the transformation of 18R→10H was detected in Mg-9.0Y-1.7Al(at.%)alloy,while the coexistence of 18R and 10H was observed in Mg-14.2Y-12.8Al(at.%)alloy.It was found that the LPSO phases were non-stoichiometric compounds with ternary solubilities.The 18R can dissolve up to 7.21 at.%-8.37 at.%Al and 10.75 at.%-12.01 at.%Y,while the 10H can dissolve up to 9.35 at.%-10.37 at.%Al and 14.50 at.%-14.94 at.%Y.All of the experimental re-sults were used to construct the isothermal sections,which is conducive to the design of Mg-Y-Al alloys.
文摘Analysis electron microtechnique (AEM) and high resolution electron microtechnique (HREM) studies were conducted on a spray deposition Al 8.5Fe 1.3V 1.7Si(mass fraction, %) alloy to determine the characteristics of the intermetallic phases. The results show that the striking characteristics of the microstructures in as deposited and as extruded alloys indicate the presence of a large amounts of homogeneously distributed fine particles and a few coarse particles, while small amount of eutectics consisted of α (Al) and α AlFeSi are found in local zone in as deposited alloy. The fine particle is identified to be bcc α AlFeSi phase, and the coarse particles are monoclinic α Al 13 Fe 4 equilibrium phase, bcc α AlFeSi phase and newly found hexagonal h AlFeSi metastable phase. In α Al 13 Fe 4 , stacking faults on (100) and (001) plane and microtwin on (100) twinning plane are frequently observed. The extra reflection spots in α AlFeSi reflection pattern can be induced by α AlFeSi superstructure. The hexagonal metastable phase transforms to bcc phase, and the compositions of two phases are very similar. A close crystallographic orientation relationship between hexagonal and bcc phases are determined, and HREM image shows that the interface between them is coherent. [
文摘Copper-manganese-aluminum （CMA） alloys, containing small additions of Fe, Ni, and Si, exhibit good strength and remarkable corrosion resistance against sea water. The alloys are used in as-cast condition, and their microstructure can show wide variations. The morphology, crystallography and composition of the phases presented in an as-cast （CMA） alloy of nominal composition Cu-14%Mn-8%Al-3%Fe-2%Ni were investigated using optical, electron optical, and microprobe analytical techniques. The as-cast microstructure consisted of the grains of fcc α and bcc β-phases alongwith intermetallic precipitates of various morphologies. The room temperature microstructure exhibited four different types of precipitates inside the α-grains： the ＇large＇ dendritic-shaped particles and the cuboid-shaped precipitates, which were rich in Fe and Mn and had an fcc structure, while the ＇small＇ dendritic-shaped particles and the globular precipitates were based on FeaAI and had DO3 structure. These four different morphologies of intermetallic precipitates exhibited discrete orientation-relationships with the α-matrix. The β-grains only contained very small cuboid shaped precipitates, which could only be resolved through transmission electron microscopy. These precipitates were found to be based on Fe3Al and had the DO3 structure.
基金supported financially by the National Natural Science Foundation of China(Nos.51701200,11804030 and 21521092)the Project for Science and Technology Development of Jilin Province(Nos.20180520004JH,201602011004GX,20170414001GH and 20180520160JH)
文摘The detailed structures and the corresponding formation mechanisms of the well-known Al_(10)RE_2Mn_7 phase in the conventional die-cast Mg–4Al–4RE–0.3Mn alloy were thoroughly investigated using transmission electron microscopy(TEM). The results indicate that the Al_(10)RE_2Mn_7 phase ordinarily contains both normal (111) twins and orientation twins.Both detailed TEM observations and density functional theory calculations indicate that the Al_(10)RE_2Mn_7 phase is transferred from the Al_8REMn_4 phase following an orientation relationship as [010]_(Al_8REMn_4)//[101]_(Al_(10)RE_2Mn_7) and (101)_(Al_8REMn_4)//(110)_(Al_(10)RE_2Mn_7). Moreover, forming orientation twins in the Al_(10)RE_2Mn_7 phase is attributed to the blurry regions at incoherent twin boundaries in the Al_8REMn_4 phase. Finally, these formed orientation twins result in the (111) twins in the Al_(10)RE_2Mn_7 phase.
文摘The study of dynamic relationships between the atmospheric carbon dioxide and the Earth’s global temperature in the current changing climate supported the notion that the trend in the global temperature followed the trend in the atmospheric CO2 before the climate hiatus that started in the beginning of the 21st century. During the hiatus period, the heat trapped by the atmospheric CO2 is going mostly to the ocean. This conclusion is supported by comparison of the CO2 trend with the trend in the ocean heat content. The phase relationships between the CO2 and temperature are more complicated after the removal of the trends. The phase relationships are chaotic on time scales shorter than the annual time scale. During 1986-2008, the atmospheric CO2 changed in an-ti-phase with the global temperature. The phase relationship reversed in 1979 and after 2010. The atmospheric CO2 was in-phase with the global temperature on the El Nino time scale (2.3 - 7 years) except during very strong El Nino years in 1991-1999 when CO2 led the global temperature.
文摘T_(1)'phase in Al-2.6Li-1.3Cu alloy was studied systematically by selected area clectron diffraction,serial rotation and matrix analysis of electron diffraction pattern.The results show that the crystalline structure of T,’phase is orthohombic.The lattice parameters are a=0.2876nm,b=0.86nm,c=0.406nm,and orientation relationship with the matrix is(010)://(110)。,[001]T_(1)'//[100]。.
文摘How to improve the probability of registration and precision of localization is a hard problem, which is desiderated to solve. The two basic approaches (normalized cross-correlation and phase correlation) for image registration are analysed, two improved approaches based on spatial-temporal relationship are presented. This method adds the correlation matrix according to the displacements in x- cirection and y- directions, and the registration pose is searched in the added matrix. The method overcomes the shortcoming that the probability of registration decreasing with area increasing owing to geometric distortion, improves the probability and the robustness of registration.
