Diamond-copper composites were prepared by powder metallurgy,in which the diamond particles were pre-coated by magnetic sputtering with copper alloy containing a small amount of carbide forming elements(including B,Cr...Diamond-copper composites were prepared by powder metallurgy,in which the diamond particles were pre-coated by magnetic sputtering with copper alloy containing a small amount of carbide forming elements(including B,Cr,Ti,and Si).The influence of the carbide forming element additives on the microstructure and thermal conductivity of diamond composites was investigated.It is found that the composites fabricated with Cu-0.5B coated diamond particles has a relatively higher density and its thermal conductivity approaches 300 W/(m·K).Addition of 0.5%B improves the interfacial bonding and decreases thermal boundary resistance between diamond and Cu,while addition of 1%Cr makes the interfacial layer break away from diamond surface.The actual interfacial thermal conductivity of the composites with Cu-0.5B alloy coated on diamond is much higher than that of the Cu-1Cr layer,which suggests that the intrinsic thermal conductivity of the interfacial layer is an important factor for improving the thermal conductivity of the diamond composites.展开更多
The microstructure and aging behavior of spray formed Al-Zn-Mg-Cu alloys were investigated as a function of alloying element addition. It is revealed that the grains of the as-deposited alloys are refined with increas...The microstructure and aging behavior of spray formed Al-Zn-Mg-Cu alloys were investigated as a function of alloying element addition. It is revealed that the grains of the as-deposited alloys are refined with increasing Zn element, while the function of Ni addition is to reduce grain boundary particles and eutectic in the as-extruded condition. Particles containing Mg and Zn are found to increase with Zn content increasing, while the role of Ni is to reduce both the number and size of these particles. After uniform heat treatment, parts of educts in grain boundary have melted and the grains have not grown up obviously. After heat extrusion, the microstructure becomes denser and there are many precipitated phases in cross-section while there are second phase arranging along extruded direction in longitudinal section. During artificial aging, the increment of Zn content produces not much effect on peak hardness, in addition to an accelerated overage softening. An addition of about 0.13%Ni, however, gives rise to not only improved peak hardness but also an improvement of property stability at the ageing temperature.展开更多
To solve the problems of poor forming and easy adhesion of the stainless steel,Cu alloyed layer on the stainless steels was prepared by the double glow plasma surface alloying technique.The experimentalresults indicat...To solve the problems of poor forming and easy adhesion of the stainless steel,Cu alloyed layer on the stainless steels was prepared by the double glow plasma surface alloying technique.The experimentalresults indicated that the supersaturated copper dispersedly precipitated in grain interior and crystalboundaries and formed the vermicular structure.The tribologicaltests indicated that the friction coefficient of the Cu alloyed layer was lower than that of the stainless steels.The wear rate of stainless steelin the presence of Cu alloyed layer was approximately 2-fold lower than that in the absence of the alloyed layer.The results of the incrementalforming indicated that the ploughing phenomenon was not observed on the stainless steelin the presence of Cu alloyed layer during the incrementalforming,while the stainless steelpresented the deep ploughing.Therefore,Cu alloyed layer on stainless steelexhibited excellent self-lubrication and forming properties.展开更多
The copper alloys with high strength and high conductivity are important functional materials with full of potential appliances. Cu-1.2%Cr(mass fraction) alloy was prepared successfully by spray forming. The effects o...The copper alloys with high strength and high conductivity are important functional materials with full of potential appliances. Cu-1.2%Cr(mass fraction) alloy was prepared successfully by spray forming. The effects of the thermo-mechanical treatments on the microstructure and mechanical properties of the alloy were studied and the strengthening mechanism was analyzed. The results show that the spray-formed Cu-1.2%Cr alloy has excellent mechanical properties with optimized thermo-mechanical treatments and the main strengthening mechanism is the precipitation of the coherent chromium precipitates, which is resulted from the decomposition of the supersaturated solid solution.展开更多
The formation and thermal stabilities of Cu46.25Zr46.25xAl7.5Erx (x=0 to 8) bulk metallic glasses (BMGs) were investigated. The addition of a small amount of Er (2at%) for replacing Zr effectively improves the glass-f...The formation and thermal stabilities of Cu46.25Zr46.25xAl7.5Erx (x=0 to 8) bulk metallic glasses (BMGs) were investigated. The addition of a small amount of Er (2at%) for replacing Zr effectively improves the glass-forming ability of Cu46.25Zr46.25Al7.5 alloy, and the glassy rod with a diameter of at least 12 mm can be formed. The glass transition temperature (Tg), temperature interval of su- percooled liquid region △Tx (=Tx-Tg), and reduced glass transition temperature Trg (=Tg/Tl) of Cu46.25Zr44.25Al7.5Er2 glassy alloy are 699 K, 62 K and 0.607, respectively.展开更多
Based on the research content and conception of dynamics of tectonic ore-forming processes, with the focus on the dynamics and processes of mineral source, ore formation, transport, accumulation, dissipation and miner...Based on the research content and conception of dynamics of tectonic ore-forming processes, with the focus on the dynamics and processes of mineral source, ore formation, transport, accumulation, dissipation and mineralization in response to magmatic invasion and metallogenic fluid under tectonic stress, this paper deals with the ore-finding method of fault tectono-geochemistry and its application on the basis of ore deposit genesis, "giant pressure shadow" structure and ore-finding method of tectonic stress field in the Tongchang orefield, expounds the rules of magmatic emplacement and ore fluid migration and concentration under the control of the structural stress field, hence providing the theoretical basis for the localization and prognosis of concealed ores. The fault tectono-geochemical features show that the Cu-Au polymetallic ore deposits (mineralization) in the orefield are closely related with volcano-(exhalation) sedimentation, magmatism and tectono-reworking. Fault tectono-geochemical anomalies can be applied to prognosis of metallogenetic target areas for ore exploration and can provide strong evidence of "giant pressure shadow" structure. In addition, quite a number of important target areas have been defined in combination with the characteristics of the tectonic stress field, and part of the target areas have been proved by practical activities.展开更多
Ribbons of amorphous Cu-Ti-Ni alloys were prepared by the melt spinning method. The amorphous structure of these ribbons was confirmed by X-ray diffractametry and transmission electron microscopy. The effect of Ni on ...Ribbons of amorphous Cu-Ti-Ni alloys were prepared by the melt spinning method. The amorphous structure of these ribbons was confirmed by X-ray diffractametry and transmission electron microscopy. The effect of Ni on the glass-forming ability of Cu-Ti-based alloys was studied by differential scanning calorimetry(DSC). It is found that the supercooled liquid region, ?Tx value shows the maximum value of 61℃ at x=10 in the Cu50Ti50?xNix (x=0, 5, 10, 15 mole fraction, %) system. And the reduced glass transition temperature, Trg, is smaller than 0.45. The glass forming ability(GFA) of Cu-Ti alloy is not effectively promoted by Ni addition.展开更多
Ti 61.67 Zr 17.15 Ni 14.80 Cu 6.38 (atom fraction, %) metallic glass has applications in brazing. Using the hammer and anvil technique, Ti 61.67 Zr 17.15 Ni 14.80 Cu 6.38 metallic glass was prepared. The crystallizati...Ti 61.67 Zr 17.15 Ni 14.80 Cu 6.38 (atom fraction, %) metallic glass has applications in brazing. Using the hammer and anvil technique, Ti 61.67 Zr 17.15 Ni 14.80 Cu 6.38 metallic glass was prepared. The crystallization behavior for this metallic glass was investigated by differential scanning calorimetry(DSC), X ray diffractometry(XRD) and transmission electron microscopy(TEM). There are three stages in DSC curves of crystallization. The reduced glass temperature T rg is 0.42. The kinetic parameters of crystallization were calculated by a set of equations of the maximum crystallization rate. The crystalline phase formed in the MSI(Metastable stage I) is Zr 2Cu, in the MSII is α Ti and in the MSIII is Ti 2Ni. This kind of alloy has lower glass forming ability, and the Ti 61.67 Zr 17.15 Ni 14.80 Cu 6.38 metallic glass has lower thermal stability.展开更多
基金Project(82129)supported by the Innovative Foundation of Science and Technology of General Research Institute of Nonferrous Metals,China
文摘Diamond-copper composites were prepared by powder metallurgy,in which the diamond particles were pre-coated by magnetic sputtering with copper alloy containing a small amount of carbide forming elements(including B,Cr,Ti,and Si).The influence of the carbide forming element additives on the microstructure and thermal conductivity of diamond composites was investigated.It is found that the composites fabricated with Cu-0.5B coated diamond particles has a relatively higher density and its thermal conductivity approaches 300 W/(m·K).Addition of 0.5%B improves the interfacial bonding and decreases thermal boundary resistance between diamond and Cu,while addition of 1%Cr makes the interfacial layer break away from diamond surface.The actual interfacial thermal conductivity of the composites with Cu-0.5B alloy coated on diamond is much higher than that of the Cu-1Cr layer,which suggests that the intrinsic thermal conductivity of the interfacial layer is an important factor for improving the thermal conductivity of the diamond composites.
基金Project(2001AA332030) supported by the Hi-tech Research and Development Program of China
文摘The microstructure and aging behavior of spray formed Al-Zn-Mg-Cu alloys were investigated as a function of alloying element addition. It is revealed that the grains of the as-deposited alloys are refined with increasing Zn element, while the function of Ni addition is to reduce grain boundary particles and eutectic in the as-extruded condition. Particles containing Mg and Zn are found to increase with Zn content increasing, while the role of Ni is to reduce both the number and size of these particles. After uniform heat treatment, parts of educts in grain boundary have melted and the grains have not grown up obviously. After heat extrusion, the microstructure becomes denser and there are many precipitated phases in cross-section while there are second phase arranging along extruded direction in longitudinal section. During artificial aging, the increment of Zn content produces not much effect on peak hardness, in addition to an accelerated overage softening. An addition of about 0.13%Ni, however, gives rise to not only improved peak hardness but also an improvement of property stability at the ageing temperature.
基金Funded by the National Natural Science Foundation of China(Nos.51245010 and 51405242)the Natural Science Foundation of Jiangsu Province,China(No.BK2012463)
文摘To solve the problems of poor forming and easy adhesion of the stainless steel,Cu alloyed layer on the stainless steels was prepared by the double glow plasma surface alloying technique.The experimentalresults indicated that the supersaturated copper dispersedly precipitated in grain interior and crystalboundaries and formed the vermicular structure.The tribologicaltests indicated that the friction coefficient of the Cu alloyed layer was lower than that of the stainless steels.The wear rate of stainless steelin the presence of Cu alloyed layer was approximately 2-fold lower than that in the absence of the alloyed layer.The results of the incrementalforming indicated that the ploughing phenomenon was not observed on the stainless steelin the presence of Cu alloyed layer during the incrementalforming,while the stainless steelpresented the deep ploughing.Therefore,Cu alloyed layer on stainless steelexhibited excellent self-lubrication and forming properties.
文摘The copper alloys with high strength and high conductivity are important functional materials with full of potential appliances. Cu-1.2%Cr(mass fraction) alloy was prepared successfully by spray forming. The effects of the thermo-mechanical treatments on the microstructure and mechanical properties of the alloy were studied and the strengthening mechanism was analyzed. The results show that the spray-formed Cu-1.2%Cr alloy has excellent mechanical properties with optimized thermo-mechanical treatments and the main strengthening mechanism is the precipitation of the coherent chromium precipitates, which is resulted from the decomposition of the supersaturated solid solution.
基金This work was financially supported by the National Natural Science Foundation of China (No.50225103, 50471001, and 50631010).
文摘The formation and thermal stabilities of Cu46.25Zr46.25xAl7.5Erx (x=0 to 8) bulk metallic glasses (BMGs) were investigated. The addition of a small amount of Er (2at%) for replacing Zr effectively improves the glass-forming ability of Cu46.25Zr46.25Al7.5 alloy, and the glassy rod with a diameter of at least 12 mm can be formed. The glass transition temperature (Tg), temperature interval of su- percooled liquid region △Tx (=Tx-Tg), and reduced glass transition temperature Trg (=Tg/Tl) of Cu46.25Zr44.25Al7.5Er2 glassy alloy are 699 K, 62 K and 0.607, respectively.
基金This research project was granted jointly by the Funds for Program for NSF (40863002)NCET in University (NCET-04-917)the Project for the Distinguishing Discipline of KUST (2008)
文摘Based on the research content and conception of dynamics of tectonic ore-forming processes, with the focus on the dynamics and processes of mineral source, ore formation, transport, accumulation, dissipation and mineralization in response to magmatic invasion and metallogenic fluid under tectonic stress, this paper deals with the ore-finding method of fault tectono-geochemistry and its application on the basis of ore deposit genesis, "giant pressure shadow" structure and ore-finding method of tectonic stress field in the Tongchang orefield, expounds the rules of magmatic emplacement and ore fluid migration and concentration under the control of the structural stress field, hence providing the theoretical basis for the localization and prognosis of concealed ores. The fault tectono-geochemical features show that the Cu-Au polymetallic ore deposits (mineralization) in the orefield are closely related with volcano-(exhalation) sedimentation, magmatism and tectono-reworking. Fault tectono-geochemical anomalies can be applied to prognosis of metallogenetic target areas for ore exploration and can provide strong evidence of "giant pressure shadow" structure. In addition, quite a number of important target areas have been defined in combination with the characteristics of the tectonic stress field, and part of the target areas have been proved by practical activities.
基金Project(50471052) supported by the National Natural Science Foundation of China Project(Z2004F02) supported by the Natural Science Foundation of Shandong Province, China Project(2005422024) supported by the Specialized Research Fund for the Doctoral Program of Higher Education
文摘Ribbons of amorphous Cu-Ti-Ni alloys were prepared by the melt spinning method. The amorphous structure of these ribbons was confirmed by X-ray diffractametry and transmission electron microscopy. The effect of Ni on the glass-forming ability of Cu-Ti-based alloys was studied by differential scanning calorimetry(DSC). It is found that the supercooled liquid region, ?Tx value shows the maximum value of 61℃ at x=10 in the Cu50Ti50?xNix (x=0, 5, 10, 15 mole fraction, %) system. And the reduced glass transition temperature, Trg, is smaller than 0.45. The glass forming ability(GFA) of Cu-Ti alloy is not effectively promoted by Ni addition.
文摘Ti 61.67 Zr 17.15 Ni 14.80 Cu 6.38 (atom fraction, %) metallic glass has applications in brazing. Using the hammer and anvil technique, Ti 61.67 Zr 17.15 Ni 14.80 Cu 6.38 metallic glass was prepared. The crystallization behavior for this metallic glass was investigated by differential scanning calorimetry(DSC), X ray diffractometry(XRD) and transmission electron microscopy(TEM). There are three stages in DSC curves of crystallization. The reduced glass temperature T rg is 0.42. The kinetic parameters of crystallization were calculated by a set of equations of the maximum crystallization rate. The crystalline phase formed in the MSI(Metastable stage I) is Zr 2Cu, in the MSII is α Ti and in the MSIII is Ti 2Ni. This kind of alloy has lower glass forming ability, and the Ti 61.67 Zr 17.15 Ni 14.80 Cu 6.38 metallic glass has lower thermal stability.
