As a part of the systematical investigation of thephase relationships of the Zn-Al base alloys,decomposi-tion of the supersaturated phase β_S in a eutectoidZn-Al-Cu-Si alloy was studied by hardness testing,opti-cal,e...As a part of the systematical investigation of thephase relationships of the Zn-Al base alloys,decomposi-tion of the supersaturated phase β_S in a eutectoidZn-Al-Cu-Si alloy was studied by hardness testing,opti-cal,electron microscopy and X-ray diffraction.Com-pared to the monotectoid Zn-Al-Cu-Si alloy,a similarsequence of decomposition was found to consist of threestages of phase transformation,which were in accordanceto various equilibrium reactions at the temperatures abovethe ageing temperatures.展开更多
The microstructure and tensile properties of Al<sub>4</sub>C<sub>3</sub> dispersion strengthened Al composite fabricatedby reaction milling technique were investigated.It is indicated that the ...The microstructure and tensile properties of Al<sub>4</sub>C<sub>3</sub> dispersion strengthened Al composite fabricatedby reaction milling technique were investigated.It is indicated that the rod-like Al<sub>4</sub>C<sub>3</sub> dispersoidshaving a diameter of 0.02-0.03 μm and a length of 0.1-0.3μm are formed by reaction of C with Al,and uniformly distributed in the Al matrix.The interface between Al<sub>4</sub>C<sub>3</sub> and Al is clean and theinterfacial bonding is good.The matrix consists of the subgrains which have the size of 0.3-0.4μm,and most of the Al<sub>4</sub>C<sub>3</sub> dispersoids are distributed on the subgrain boundaries.The 11 vol.-%Al<sub>4</sub>C<sub>3</sub>/Al composite exhibits an UTS （ultimate tensile strength） of 400 MPa and anelongation-to-failure of 8.0%.展开更多
The 2nd International Symposium on Refrac-toties jointly organized by the Chinese Ceramic So-ciety and the Chinese Society for Metals was heldin Beijing, China, On October 30-Novemeber 2,1992. The Technical Associatio...The 2nd International Symposium on Refrac-toties jointly organized by the Chinese Ceramic So-ciety and the Chinese Society for Metals was heldin Beijing, China, On October 30-Novemeber 2,1992. The Technical Association of Refractories,Japan, the American Ceramic Society, the Refrac-tories Association of Great Britain, the GermanRefractories Association, the Australian展开更多
70-30 brass is rolled with 90% reduction bycross shear rolling in single direction with speed ra-tio 1.39.The sheet is divided into five layers alongrolling plane normal to measure macroscopic statis-tical unsymmetric...70-30 brass is rolled with 90% reduction bycross shear rolling in single direction with speed ra-tio 1.39.The sheet is divided into five layers alongrolling plane normal to measure macroscopic statis-tical unsymmetric textures in every layer are des-cribed and analysed by means of three dimensionalorientation distribution function.The results indi-cate that the main textures in every layer of brassrolled by cross shear rolling in single direction arethe same as the main textures of brass rolled byconventional rolling.But the intensities,peak posi-tions and scatters of every texture component in{110}【112】are different,namely,there is amacroscopic statistical unsymmetry.It is found thatthe textures in every layer of brass rolled by crossshear rolling in single direction can be considered asthe textures of brass rolled by common rolling insingle direction at identical shear forces,themacroscopic statistical unsymmetry depends on theshear forces which are exerted on the layer.展开更多
A study has been made of the fatigue crackgrowth in an Al-Li alloy 2091 in 3.5%NaCl solu-tion and at an elevated temperature of 130℃.Theaging and environmental effects on the crackgrowth behaviour were examined.It is...A study has been made of the fatigue crackgrowth in an Al-Li alloy 2091 in 3.5%NaCl solu-tion and at an elevated temperature of 130℃.Theaging and environmental effects on the crackgrowth behaviour were examined.It is shown thatthe fatigue crack growth resistance decreases withaging.The specimen with underaged structuresshows the highest resistance to fatigue crack growthdue to more deflected crack paths and the resultinghigh crack closure levels.As compared to laborato-ry air,both 3.5% NaCl solution and elevated tem-perature of 130℃ cause an increase of near-thresh-old crack growth rates and a decrease of thresholdlevels.The elevated temperature is more effective.The effect of elevated temperature is mainly due tothe precipitate coarsening which results in anenhancement of slip irreversibility.Hydrogenembritttlement is supposed to be responsible for thedegradation of fatigue crack growth resistance in3.5%NaCl展开更多
The isothermal section of the Fe-Cu-Niternary system at 1173 K was determined bymicroprobe analysis and diffusion triple technique.The experimental results show that this isothermalsection only contains a miscibility ...The isothermal section of the Fe-Cu-Niternary system at 1173 K was determined bymicroprobe analysis and diffusion triple technique.The experimental results show that this isothermalsection only contains a miscibility gap region,andthe maximal Ni content in the miscibility gap is 44.7at.-%Ni.展开更多
The origin of low ductility at elevated tempera-ture in the cryogenic and non-magnetic steelFe-23Mn-4Al-5Cr-0.3C was investigated bymeans of impact test at elevated temperatures,opti-cal microscope,SEM and TEM.The exp...The origin of low ductility at elevated tempera-ture in the cryogenic and non-magnetic steelFe-23Mn-4Al-5Cr-0.3C was investigated bymeans of impact test at elevated temperatures,opti-cal microscope,SEM and TEM.The experimentalresults indicate that the impact toughness lowerswith increasing testing temperature,and exhibits alow trough of ductility from 865℃ to 1050℃ and apeak value at 1150℃.The intergranular fractureoccurs in the temperature region of low ductilityand the transgranular ductile rupture below this re-gion principally.There is a process of precipitating,gathering,growing,and dissolution of carbide（FeMnCr）<sub>23</sub>C<sub>6</sub> and AlN between 500℃ and1000℃.The coalescence of microvoids caused bythe process at grain boundaries results in theintergranular fracture and the low ductility at ele-vated temperatures.展开更多
An investigation has been made of the disloca-tion distribution and dislocation free zone near thecrack tip in bulk Fe-3% Si single crystal duringdeformation in SEM.It has been found that anumber of dislocations were ...An investigation has been made of the disloca-tion distribution and dislocation free zone near thecrack tip in bulk Fe-3% Si single crystal duringdeformation in SEM.It has been found that anumber of dislocations were emitted from the cracktip during deformation.After that,the dislocationsmoved rapidly away from the crack tip,which indi-cated that they were strongly repelled by the stressfield at the crack tip.Between the crack tip and theplastic zone there is a region of dislocation-free,which is referred to as dislocation-free zone (DFZ).The length of DFZs is roughly estimated 100μm which is much longer than that found in thinfoil specimen.The variation of dislocation densityas a function of the distance from the crack tip wasmeasured,which showed that the dislocations areinversely piled up in the plastic zone.The length ofDFZs increased with both the length of pre-crackand the amplitude of applied stress.展开更多
The relationship between the high-frequency magnetic properties and surface structure of the amorphous[Co<sub>0.94-x</sub>Fe<sub>0.06</sub>（MnMo）<sub>x</sub>]<sub>77</sub...The relationship between the high-frequency magnetic properties and surface structure of the amorphous[Co<sub>0.94-x</sub>Fe<sub>0.06</sub>（MnMo）<sub>x</sub>]<sub>77</sub>（SiB）<sub>23</sub> alloys annealed at 400-500℃ then control-cooled was investigated usingXRD,TEM and XPS techniques.The results have shown that the high-frequency losses of the present alloys ob-viously reduced after suitable treatment.A crystalline layer with ultrafine grains of γ-Co formed on the surface ofthe amorphous ribbons.The size of the grains is 10-20 nm.The thickness of the layer is less than 0.1 μm.The sur-face of the crystalline layer is covered with an extremely thin oxide film which is very uniform and dense withthickness of less than 30 nm,the size of grains of the oxide is less than 10 nm.These ultrafine grains and thedense oxide film effectively refine the magnetic domains and increase the resistance of the layers of the magneticcore,consequently the losses at high frequency are fairly reduced.展开更多
The phase transformation and deformationmechanism of the alloy based on composition Ti<sub>3</sub>Alwith addition of Nb,V,Mo have been studied by useof transmission electron microscopy （TEM）.It hasbeen s...The phase transformation and deformationmechanism of the alloy based on composition Ti<sub>3</sub>Alwith addition of Nb,V,Mo have been studied by useof transmission electron microscopy （TEM）.It hasbeen shown that the orientation relationship ofα<sub>2</sub> phase transformed from β phase is:（0001）α<sub>2</sub>//（l10）β,[1210]α<sub>2</sub>//[111]β.The present dislocationslip systems in α<sub>2</sub> phase are （1100）[0001] and（1100）【1120】.There also exist α<sub>2</sub> twins whichhave new twin relationship and the twin plane is（2021）.展开更多
By means of X-ray diffraction investigationsand electric resistivity measurements the tempera-ture dependence of phase structure and supercon-ductivity in YBa<sub>2</sub>Cu<sub>3</sub>O<sub&...By means of X-ray diffraction investigationsand electric resistivity measurements the tempera-ture dependence of phase structure and supercon-ductivity in YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7<sub>x</sub></sub> over the temperaturerange of 20℃-950℃ have been studied.The latticeparameters a,b and c as well as conductivityas a function of annealing temperatures canbe roughly divided into three zones which aresuperconductive orthorhombic structure 1（a【bc/3）at 20℃-500℃,normal conductive orthorhombicstructure 2（a【b【c/3）from 550℃ to about 750℃and semiconductive-like tetragonal structure（a=b【c/3）from about 800℃ to 950℃.However,the boundaries of the three zones is not muchdistinctive because there is a continuous transi-tion from the orthorhombic to tetragonal struc-ture.Furthermore,the processes of orthorhom-bic-tetragonal transition in the range of350℃-950℃ are not only continuous but alsoreversible.The isothermal transition oforthorhombic 2 to orthorhombic 1 occurs at350℃-500℃,while the maximum rate of transitionand high T<sub>c</sub> superconductivity can be obtainedat about 460℃.This process of isothermaltransition depends on the ordering of oxygenatoms or vacancies and the thermodynamicequilibrium to allow the oxygen diffusion.展开更多
In present investigation exchange interactions of Pr<sub>n+1</sub>Co<sub>3n+5</sub>B<sub>2n</sub>-type compounds have been evalu-ated in the light of molecular-field theory. The exc...In present investigation exchange interactions of Pr<sub>n+1</sub>Co<sub>3n+5</sub>B<sub>2n</sub>-type compounds have been evalu-ated in the light of molecular-field theory. The exchange interactions and ferromagnetism in thesecompounds are discussed in terms of lattice parameters and interatomic distance between Co atom.展开更多
In present work,Fe-3%Si alloy specimens with various degrees of cold working and various grainsizes were chosen to determine the effect of cold working and grain sizes on the hydrogendiffusivities by electrochemical p...In present work,Fe-3%Si alloy specimens with various degrees of cold working and various grainsizes were chosen to determine the effect of cold working and grain sizes on the hydrogendiffusivities by electrochemical permeation method and the mechanism of hydrogen trapping by dis-ocations and grain boundaries is discussed.展开更多
1.IntroductionThe research of the TD1 and TD2 al-loys based on intermetallic compound Ti<sub>3</sub>Al,which possesses high temperature capabilityfrom 650 to 700℃ was conducted.However,the limitation used...1.IntroductionThe research of the TD1 and TD2 al-loys based on intermetallic compound Ti<sub>3</sub>Al,which possesses high temperature capabilityfrom 650 to 700℃ was conducted.However,the limitation used at high temperature isimposed by oxidation and degradation ofcreep strength,and relatively little know-展开更多
1.IntroductionDunn and Farrington[1]found that theNa ion in Naβ″-alumina single crystal canbe exchanged completely or partially withGd<sup>3+</sup>,Nd<sup>3+</sup>,Eu<sup>3+</sup>...1.IntroductionDunn and Farrington[1]found that theNa ion in Naβ″-alumina single crystal canbe exchanged completely or partially withGd<sup>3+</sup>,Nd<sup>3+</sup>,Eu<sup>3+</sup>,Yb<sup>3+</sup>,Sm<sup>3+</sup>,Tb<sup>3+</sup>,Dy<sup>3+</sup>,Bi<sup>3+</sup>and Pr<sup>3+</sup>ions,but no reports havebeen published about the ion exchange reac-tion between La3+ and Naβ″-alumina.If anion exchanged polycrystalline β″-alumina isavailable and its ionic conductivity is highenough to be applied as a solid electrolyte inthe galvanic cell,it can be used in展开更多
1 Introduction The method of acoustic emission (AE)as a new technique to study the processesin metals and alloys in the solid phase hasbeen widely used and developed since thelast 20 years. Martensite transformationis...1 Introduction The method of acoustic emission (AE)as a new technique to study the processesin metals and alloys in the solid phase hasbeen widely used and developed since thelast 20 years. Martensite transformationis diffusionless. Because of changing fromone crystal structure to another by coopera-tive shear process the interfacial展开更多
The quench transfomation in a Ti-10V-2Fe-3Alnear B-titanium alloy was studied by meansof X-ray diffraction, transmission electronmicroscopy, and optical micyoscopy. The quenchingtemperatures were above and below the ...The quench transfomation in a Ti-10V-2Fe-3Alnear B-titanium alloy was studied by meansof X-ray diffraction, transmission electronmicroscopy, and optical micyoscopy. The quenchingtemperatures were above and below the β transustemperature. The phase constitutions of specimensquenched from various solution temperatureswere identified and the phase morphologies wereexamined. In addition, the relationship betweenphase lattice parameters and quenching tempera-tures was given for α, β and α <sup>11</sup> phases. Thisalloy has a tendency of precipitation of athermalω phase and formation of stress induced α<sup>11</sup> mar-tensite from β phase during quenching. Quenchedfrom the temperatures above the β transus tem-perature, the alloy mainly consists of β phase,a small amount of α<sup>11</sup> martensite and athemalω phase aye also present in the alloy. Afterquenching from the temperatures below the βtransus temperature, the α phase appeaysin the alloy in addition to the phases mentionedabove.展开更多
Since the discovery of high T_c super-conductor, much effort was made toits application. More and more evidencehas revealed that most promising fieldof high T_c superconductor first to havesuccess must be the microele...Since the discovery of high T_c super-conductor, much effort was made toits application. More and more evidencehas revealed that most promising fieldof high T_c superconductor first to havesuccess must be the microelectronics andcomputer. Superconductor films for mi-croelectronic application are preparedby PVD method, such as electron beamevaporation, pulsed laser evaporation andmagnetron sputtering. In this paper, thepreliminary results of ion beam sputteringdeposition of YBaCuO film are展开更多
1.IntroductionSuperplasticity is not merely a specialphenomenon for certain specific alley,but isone of the intrinsic properties of metallicmaterials[1].When the internal and externalconditions are suitable,superplast...1.IntroductionSuperplasticity is not merely a specialphenomenon for certain specific alley,but isone of the intrinsic properties of metallicmaterials[1].When the internal and externalconditions are suitable,superplasticity ofmetal materials will be presented.展开更多
The microstructure of both {10（?）1} and{10（?）0} （directions perpendicular to the {10（?）1}and {10（?）0} planes） α-Si<sub>3</sub>N<sub>4</sub> whiskers were investi-gated by high resolu...The microstructure of both {10（?）1} and{10（?）0} （directions perpendicular to the {10（?）1}and {10（?）0} planes） α-Si<sub>3</sub>N<sub>4</sub> whiskers were investi-gated by high resolution electron microscopy（HREM）.On one side of the {10（?）1}α-Si<sub>3</sub>N<sub>4</sub> whiskers many planar defects were ob-served,two kinds of micrograins on one side of the{10（?）0} whiskers were found.In one type,sepa-rated α-Si<sub>3</sub>N<sub>4</sub> （28 H） micrograins had the sameorientation with respect to the matrix whisker;inthe other type,connected polymicrograins consistedof both α-and β-Si<sub>3</sub>N<sub>4</sub> （14H）.展开更多
文摘As a part of the systematical investigation of thephase relationships of the Zn-Al base alloys,decomposi-tion of the supersaturated phase β_S in a eutectoidZn-Al-Cu-Si alloy was studied by hardness testing,opti-cal,electron microscopy and X-ray diffraction.Com-pared to the monotectoid Zn-Al-Cu-Si alloy,a similarsequence of decomposition was found to consist of threestages of phase transformation,which were in accordanceto various equilibrium reactions at the temperatures abovethe ageing temperatures.
文摘The microstructure and tensile properties of Al<sub>4</sub>C<sub>3</sub> dispersion strengthened Al composite fabricatedby reaction milling technique were investigated.It is indicated that the rod-like Al<sub>4</sub>C<sub>3</sub> dispersoidshaving a diameter of 0.02-0.03 μm and a length of 0.1-0.3μm are formed by reaction of C with Al,and uniformly distributed in the Al matrix.The interface between Al<sub>4</sub>C<sub>3</sub> and Al is clean and theinterfacial bonding is good.The matrix consists of the subgrains which have the size of 0.3-0.4μm,and most of the Al<sub>4</sub>C<sub>3</sub> dispersoids are distributed on the subgrain boundaries.The 11 vol.-%Al<sub>4</sub>C<sub>3</sub>/Al composite exhibits an UTS （ultimate tensile strength） of 400 MPa and anelongation-to-failure of 8.0%.
文摘The 2nd International Symposium on Refrac-toties jointly organized by the Chinese Ceramic So-ciety and the Chinese Society for Metals was heldin Beijing, China, On October 30-Novemeber 2,1992. The Technical Association of Refractories,Japan, the American Ceramic Society, the Refrac-tories Association of Great Britain, the GermanRefractories Association, the Australian
文摘70-30 brass is rolled with 90% reduction bycross shear rolling in single direction with speed ra-tio 1.39.The sheet is divided into five layers alongrolling plane normal to measure macroscopic statis-tical unsymmetric textures in every layer are des-cribed and analysed by means of three dimensionalorientation distribution function.The results indi-cate that the main textures in every layer of brassrolled by cross shear rolling in single direction arethe same as the main textures of brass rolled byconventional rolling.But the intensities,peak posi-tions and scatters of every texture component in{110}【112】are different,namely,there is amacroscopic statistical unsymmetry.It is found thatthe textures in every layer of brass rolled by crossshear rolling in single direction can be considered asthe textures of brass rolled by common rolling insingle direction at identical shear forces,themacroscopic statistical unsymmetry depends on theshear forces which are exerted on the layer.
文摘A study has been made of the fatigue crackgrowth in an Al-Li alloy 2091 in 3.5%NaCl solu-tion and at an elevated temperature of 130℃.Theaging and environmental effects on the crackgrowth behaviour were examined.It is shown thatthe fatigue crack growth resistance decreases withaging.The specimen with underaged structuresshows the highest resistance to fatigue crack growthdue to more deflected crack paths and the resultinghigh crack closure levels.As compared to laborato-ry air,both 3.5% NaCl solution and elevated tem-perature of 130℃ cause an increase of near-thresh-old crack growth rates and a decrease of thresholdlevels.The elevated temperature is more effective.The effect of elevated temperature is mainly due tothe precipitate coarsening which results in anenhancement of slip irreversibility.Hydrogenembritttlement is supposed to be responsible for thedegradation of fatigue crack growth resistance in3.5%NaCl
文摘The isothermal section of the Fe-Cu-Niternary system at 1173 K was determined bymicroprobe analysis and diffusion triple technique.The experimental results show that this isothermalsection only contains a miscibility gap region,andthe maximal Ni content in the miscibility gap is 44.7at.-%Ni.
基金The project was supported by the National Natural Science Foundation of China:Grant No.5870006
文摘The origin of low ductility at elevated tempera-ture in the cryogenic and non-magnetic steelFe-23Mn-4Al-5Cr-0.3C was investigated bymeans of impact test at elevated temperatures,opti-cal microscope,SEM and TEM.The experimentalresults indicate that the impact toughness lowerswith increasing testing temperature,and exhibits alow trough of ductility from 865℃ to 1050℃ and apeak value at 1150℃.The intergranular fractureoccurs in the temperature region of low ductilityand the transgranular ductile rupture below this re-gion principally.There is a process of precipitating,gathering,growing,and dissolution of carbide（FeMnCr）<sub>23</sub>C<sub>6</sub> and AlN between 500℃ and1000℃.The coalescence of microvoids caused bythe process at grain boundaries results in theintergranular fracture and the low ductility at ele-vated temperatures.
文摘An investigation has been made of the disloca-tion distribution and dislocation free zone near thecrack tip in bulk Fe-3% Si single crystal duringdeformation in SEM.It has been found that anumber of dislocations were emitted from the cracktip during deformation.After that,the dislocationsmoved rapidly away from the crack tip,which indi-cated that they were strongly repelled by the stressfield at the crack tip.Between the crack tip and theplastic zone there is a region of dislocation-free,which is referred to as dislocation-free zone (DFZ).The length of DFZs is roughly estimated 100μm which is much longer than that found in thinfoil specimen.The variation of dislocation densityas a function of the distance from the crack tip wasmeasured,which showed that the dislocations areinversely piled up in the plastic zone.The length ofDFZs increased with both the length of pre-crackand the amplitude of applied stress.
文摘The relationship between the high-frequency magnetic properties and surface structure of the amorphous[Co<sub>0.94-x</sub>Fe<sub>0.06</sub>（MnMo）<sub>x</sub>]<sub>77</sub>（SiB）<sub>23</sub> alloys annealed at 400-500℃ then control-cooled was investigated usingXRD,TEM and XPS techniques.The results have shown that the high-frequency losses of the present alloys ob-viously reduced after suitable treatment.A crystalline layer with ultrafine grains of γ-Co formed on the surface ofthe amorphous ribbons.The size of the grains is 10-20 nm.The thickness of the layer is less than 0.1 μm.The sur-face of the crystalline layer is covered with an extremely thin oxide film which is very uniform and dense withthickness of less than 30 nm,the size of grains of the oxide is less than 10 nm.These ultrafine grains and thedense oxide film effectively refine the magnetic domains and increase the resistance of the layers of the magneticcore,consequently the losses at high frequency are fairly reduced.
文摘The phase transformation and deformationmechanism of the alloy based on composition Ti<sub>3</sub>Alwith addition of Nb,V,Mo have been studied by useof transmission electron microscopy （TEM）.It hasbeen shown that the orientation relationship ofα<sub>2</sub> phase transformed from β phase is:（0001）α<sub>2</sub>//（l10）β,[1210]α<sub>2</sub>//[111]β.The present dislocationslip systems in α<sub>2</sub> phase are （1100）[0001] and（1100）【1120】.There also exist α<sub>2</sub> twins whichhave new twin relationship and the twin plane is（2021）.
文摘By means of X-ray diffraction investigationsand electric resistivity measurements the tempera-ture dependence of phase structure and supercon-ductivity in YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7<sub>x</sub></sub> over the temperaturerange of 20℃-950℃ have been studied.The latticeparameters a,b and c as well as conductivityas a function of annealing temperatures canbe roughly divided into three zones which aresuperconductive orthorhombic structure 1（a【bc/3）at 20℃-500℃,normal conductive orthorhombicstructure 2（a【b【c/3）from 550℃ to about 750℃and semiconductive-like tetragonal structure（a=b【c/3）from about 800℃ to 950℃.However,the boundaries of the three zones is not muchdistinctive because there is a continuous transi-tion from the orthorhombic to tetragonal struc-ture.Furthermore,the processes of orthorhom-bic-tetragonal transition in the range of350℃-950℃ are not only continuous but alsoreversible.The isothermal transition oforthorhombic 2 to orthorhombic 1 occurs at350℃-500℃,while the maximum rate of transitionand high T<sub>c</sub> superconductivity can be obtainedat about 460℃.This process of isothermaltransition depends on the ordering of oxygenatoms or vacancies and the thermodynamicequilibrium to allow the oxygen diffusion.
文摘In present investigation exchange interactions of Pr<sub>n+1</sub>Co<sub>3n+5</sub>B<sub>2n</sub>-type compounds have been evalu-ated in the light of molecular-field theory. The exchange interactions and ferromagnetism in thesecompounds are discussed in terms of lattice parameters and interatomic distance between Co atom.
文摘In present work,Fe-3%Si alloy specimens with various degrees of cold working and various grainsizes were chosen to determine the effect of cold working and grain sizes on the hydrogendiffusivities by electrochemical permeation method and the mechanism of hydrogen trapping by dis-ocations and grain boundaries is discussed.
文摘1.IntroductionThe research of the TD1 and TD2 al-loys based on intermetallic compound Ti<sub>3</sub>Al,which possesses high temperature capabilityfrom 650 to 700℃ was conducted.However,the limitation used at high temperature isimposed by oxidation and degradation ofcreep strength,and relatively little know-
文摘1.IntroductionDunn and Farrington[1]found that theNa ion in Naβ″-alumina single crystal canbe exchanged completely or partially withGd<sup>3+</sup>,Nd<sup>3+</sup>,Eu<sup>3+</sup>,Yb<sup>3+</sup>,Sm<sup>3+</sup>,Tb<sup>3+</sup>,Dy<sup>3+</sup>,Bi<sup>3+</sup>and Pr<sup>3+</sup>ions,but no reports havebeen published about the ion exchange reac-tion between La3+ and Naβ″-alumina.If anion exchanged polycrystalline β″-alumina isavailable and its ionic conductivity is highenough to be applied as a solid electrolyte inthe galvanic cell,it can be used in
文摘1 Introduction The method of acoustic emission (AE)as a new technique to study the processesin metals and alloys in the solid phase hasbeen widely used and developed since thelast 20 years. Martensite transformationis diffusionless. Because of changing fromone crystal structure to another by coopera-tive shear process the interfacial
文摘The quench transfomation in a Ti-10V-2Fe-3Alnear B-titanium alloy was studied by meansof X-ray diffraction, transmission electronmicroscopy, and optical micyoscopy. The quenchingtemperatures were above and below the β transustemperature. The phase constitutions of specimensquenched from various solution temperatureswere identified and the phase morphologies wereexamined. In addition, the relationship betweenphase lattice parameters and quenching tempera-tures was given for α, β and α <sup>11</sup> phases. Thisalloy has a tendency of precipitation of athermalω phase and formation of stress induced α<sup>11</sup> mar-tensite from β phase during quenching. Quenchedfrom the temperatures above the β transus tem-perature, the alloy mainly consists of β phase,a small amount of α<sup>11</sup> martensite and athemalω phase aye also present in the alloy. Afterquenching from the temperatures below the βtransus temperature, the α phase appeaysin the alloy in addition to the phases mentionedabove.
文摘Since the discovery of high T_c super-conductor, much effort was made toits application. More and more evidencehas revealed that most promising fieldof high T_c superconductor first to havesuccess must be the microelectronics andcomputer. Superconductor films for mi-croelectronic application are preparedby PVD method, such as electron beamevaporation, pulsed laser evaporation andmagnetron sputtering. In this paper, thepreliminary results of ion beam sputteringdeposition of YBaCuO film are
文摘1.IntroductionSuperplasticity is not merely a specialphenomenon for certain specific alley,but isone of the intrinsic properties of metallicmaterials[1].When the internal and externalconditions are suitable,superplasticity ofmetal materials will be presented.
文摘The microstructure of both {10（?）1} and{10（?）0} （directions perpendicular to the {10（?）1}and {10（?）0} planes） α-Si<sub>3</sub>N<sub>4</sub> whiskers were investi-gated by high resolution electron microscopy（HREM）.On one side of the {10（?）1}α-Si<sub>3</sub>N<sub>4</sub> whiskers many planar defects were ob-served,two kinds of micrograins on one side of the{10（?）0} whiskers were found.In one type,sepa-rated α-Si<sub>3</sub>N<sub>4</sub> （28 H） micrograins had the sameorientation with respect to the matrix whisker;inthe other type,connected polymicrograins consistedof both α-and β-Si<sub>3</sub>N<sub>4</sub> （14H）.
