The formation mechanism of calcium vanadate and manganese vanadate and the difference between calcium and manganese in the reaction with vanadium are basic issues in the calcification roasting and manganese roasting p...The formation mechanism of calcium vanadate and manganese vanadate and the difference between calcium and manganese in the reaction with vanadium are basic issues in the calcification roasting and manganese roasting process with vanadium slag.In this work,CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples were prepared and roasted for different time periods to illustrate and compare the diffusion reaction mechanisms.Then,the changes in the diffusion product and diffusion coefficient were investigated and calculated based on scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) analysis.Results show that with the extension of the roasting time,the diffusion reaction gradually proceeds among the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples.The regional boundaries of calcium and vanadium are easily identifiable for the CaO–V_(2)O_(5) diffusion couple.Meanwhile,for the MnO_(2)–V_(2)O_(5) diffusion couple,MnO_(2) gradually decomposes to form Mn_(2)O_(3),and vanadium diffuses into the interior of Mn_(2)O_(3).Only a part of vanadium combines with manganese to form the diffusion production layer.CaV_(2)O_(6) and MnV_(2)O_(6) are the interfacial reaction products of the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples,respectively,whose thicknesses are 39.85 and 32.13μm when roasted for 16 h.After 16 h,both diffusion couples reach the reaction equilibrium due to the limitation of diffusion.The diffusion coefficient of the CaO–V_(2)O_(5) diffusion couple is higher than that of the MnO_(2)–V_(2)O_(5) diffusion couple for the same roasting time,and the diffusion reaction between vanadium and calcium is easier than that between vanadium and manganese.展开更多
The solid-liquid method was used to prepare the continuous casting of copper cladding aluminium by liquid aluminum alloy and solid copper, and the interfacial phase formation of Al-Cu bimetal at different pouring temp...The solid-liquid method was used to prepare the continuous casting of copper cladding aluminium by liquid aluminum alloy and solid copper, and the interfacial phase formation of Al-Cu bimetal at different pouring temperatures(700, 750, 800 oC) was investigated by means of metallograph, scanning electron microscopy(SEM) and energy dispersive spectrometry(EDS) methods. The results showed that the pouring temperature of aluminum melt had an important influence on the element diffusion of Cu from the solid Cu to Al alloy melt and the reactions between Al and Cu, as well as the morphology of the Al-Cu interface. When the pouring temperature was 800 oC, there were abundant Al-Cu intermetallic compounds(IMCs) near the interface. However, a lower pouring temperature(700 oC) resulted in the formation of cavities which was detrimental to the bonding and mechanical properties. Under the conditions in this study, the good metallurgical bonding of Al-Cu was achieved at a pouring temperature of 750 oC.展开更多
Tungsten fiber reinforced Zr41.25Ti13.75Cu12.5Ni10Be22.5 metallic glass matrix composites were fabricated by means of melt infiltration casting.Their dynamic compressive tests were performed using a Hopkinson bar.The ...Tungsten fiber reinforced Zr41.25Ti13.75Cu12.5Ni10Be22.5 metallic glass matrix composites were fabricated by means of melt infiltration casting.Their dynamic compressive tests were performed using a Hopkinson bar.The relationship between the interfacial characteristics and the dynamic compressive behavior was investigated.The results indicate that the interface characteristics of composites include interfacial diffusion and interfacial reaction,and the interfacial shear strength increases when the interfacial reaction is serious.The dynamic plastic performance are improved obviously if the suitable interface reaction occurs.The failure occurs by shear and the fibers split longitudinally if there is no interface reaction or a little reaction;in contrast,holistic failure occurs if there is too much interface reaction.展开更多
In order to reveal the physical essence of the spreading process of reactive wetting,a sort of model of energy to explain the driving force and wetting mechanism was presented.The reactive wetting of molten A1 and Cu ...In order to reveal the physical essence of the spreading process of reactive wetting,a sort of model of energy to explain the driving force and wetting mechanism was presented.The reactive wetting of molten A1 and Cu Si on graphite was studied by a modified sessile drop method under a vacuum,in which the contact angles were measured by ADSA software.The thermodynamic and kinetic processes of the typical reactive wetting were focused on,the thermodynamic equations of energy relations were derived,the interfacial energy of graphite and solid-liquid interfacial energy versus time at the triple line were calculated,and the dynamics model of interface energy is established.The presented dynamics model is verified by means of experimental results,and it is shown that solid liquid interfacial energy decreases with time in exponential relationship.It provides a new method for reference to explain the process from the angle of energy.展开更多
Metal-matrix composites reinforced with shape memory alloys （SMA, including long fiber, short fiber, and particle） are ＂intelligent materials＂ with many special physical and mechanical properties, such as high dam...Metal-matrix composites reinforced with shape memory alloys （SMA, including long fiber, short fiber, and particle） are ＂intelligent materials＂ with many special physical and mechanical properties, such as high damping property, high tensile strength, and fatigue resistance. In this review article, the fabrication method, microstructure, interface reaction, modeling, and physical and mechanical properties of the composites are addressed. Particular emphasis has been given to （a） fabrication and microstructure of aluminum matrix composites reinforced with SMAs, and （b） shape memory effect on the physical and mechanical properties of the composites. While the bulk of the information is related to aluminum matrix composites, important results are now available for other metal-matrix composites.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52174277 and 51874077)the Fundamental Funds for the Central Universities,China(No.N2225032)+1 种基金the China Postdoctoral Science Foundation(No.2022M720683)the Postdoctoral Fund of Northeastern University,China。
文摘The formation mechanism of calcium vanadate and manganese vanadate and the difference between calcium and manganese in the reaction with vanadium are basic issues in the calcification roasting and manganese roasting process with vanadium slag.In this work,CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples were prepared and roasted for different time periods to illustrate and compare the diffusion reaction mechanisms.Then,the changes in the diffusion product and diffusion coefficient were investigated and calculated based on scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) analysis.Results show that with the extension of the roasting time,the diffusion reaction gradually proceeds among the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples.The regional boundaries of calcium and vanadium are easily identifiable for the CaO–V_(2)O_(5) diffusion couple.Meanwhile,for the MnO_(2)–V_(2)O_(5) diffusion couple,MnO_(2) gradually decomposes to form Mn_(2)O_(3),and vanadium diffuses into the interior of Mn_(2)O_(3).Only a part of vanadium combines with manganese to form the diffusion production layer.CaV_(2)O_(6) and MnV_(2)O_(6) are the interfacial reaction products of the CaO–V_(2)O_(5) and MnO_(2)–V_(2)O_(5) diffusion couples,respectively,whose thicknesses are 39.85 and 32.13μm when roasted for 16 h.After 16 h,both diffusion couples reach the reaction equilibrium due to the limitation of diffusion.The diffusion coefficient of the CaO–V_(2)O_(5) diffusion couple is higher than that of the MnO_(2)–V_(2)O_(5) diffusion couple for the same roasting time,and the diffusion reaction between vanadium and calcium is easier than that between vanadium and manganese.
基金financially supported by the National Natural Science Foundation of China(Nos.51074031 and 51501027)the China Postdoctoral Science Foundation(No.2015M570246)the Fundamental Research Funds for the Central Universities of China[DUT15RC(3)065]
文摘The solid-liquid method was used to prepare the continuous casting of copper cladding aluminium by liquid aluminum alloy and solid copper, and the interfacial phase formation of Al-Cu bimetal at different pouring temperatures(700, 750, 800 oC) was investigated by means of metallograph, scanning electron microscopy(SEM) and energy dispersive spectrometry(EDS) methods. The results showed that the pouring temperature of aluminum melt had an important influence on the element diffusion of Cu from the solid Cu to Al alloy melt and the reactions between Al and Cu, as well as the morphology of the Al-Cu interface. When the pouring temperature was 800 oC, there were abundant Al-Cu intermetallic compounds(IMCs) near the interface. However, a lower pouring temperature(700 oC) resulted in the formation of cavities which was detrimental to the bonding and mechanical properties. Under the conditions in this study, the good metallurgical bonding of Al-Cu was achieved at a pouring temperature of 750 oC.
基金Project(2005K06-G2)supported by the New Century Excellent Person Supporting Project of Ministry of Education of China
文摘Tungsten fiber reinforced Zr41.25Ti13.75Cu12.5Ni10Be22.5 metallic glass matrix composites were fabricated by means of melt infiltration casting.Their dynamic compressive tests were performed using a Hopkinson bar.The relationship between the interfacial characteristics and the dynamic compressive behavior was investigated.The results indicate that the interface characteristics of composites include interfacial diffusion and interfacial reaction,and the interfacial shear strength increases when the interfacial reaction is serious.The dynamic plastic performance are improved obviously if the suitable interface reaction occurs.The failure occurs by shear and the fibers split longitudinally if there is no interface reaction or a little reaction;in contrast,holistic failure occurs if there is too much interface reaction.
基金Project(50471007)supported by the National Natural Science Foundation of China
文摘In order to reveal the physical essence of the spreading process of reactive wetting,a sort of model of energy to explain the driving force and wetting mechanism was presented.The reactive wetting of molten A1 and Cu Si on graphite was studied by a modified sessile drop method under a vacuum,in which the contact angles were measured by ADSA software.The thermodynamic and kinetic processes of the typical reactive wetting were focused on,the thermodynamic equations of energy relations were derived,the interfacial energy of graphite and solid-liquid interfacial energy versus time at the triple line were calculated,and the dynamics model of interface energy is established.The presented dynamics model is verified by means of experimental results,and it is shown that solid liquid interfacial energy decreases with time in exponential relationship.It provides a new method for reference to explain the process from the angle of energy.
基金the National Natural Science Foundation of China(Nos.52174372,51974224)the Natural Science Foundation of Shaanxi Province,China(No.2020JM-047)the Fundamental Research Funds for Central Universities,China(No.xtr0118008)for their support。
基金financially supported by the National Natural Science Foundation of China (Nos.51101155 and 51331008)the National Basic Research Program of China (No.2012CB619600)
文摘Metal-matrix composites reinforced with shape memory alloys （SMA, including long fiber, short fiber, and particle） are ＂intelligent materials＂ with many special physical and mechanical properties, such as high damping property, high tensile strength, and fatigue resistance. In this review article, the fabrication method, microstructure, interface reaction, modeling, and physical and mechanical properties of the composites are addressed. Particular emphasis has been given to （a） fabrication and microstructure of aluminum matrix composites reinforced with SMAs, and （b） shape memory effect on the physical and mechanical properties of the composites. While the bulk of the information is related to aluminum matrix composites, important results are now available for other metal-matrix composites.
