Casting-cold extrusion technology was presented to fabricate aluminum/copper clad composite,and copper tubes with different sketch sections were designed.The technology of aluminum/copper clad composite fabricated by ...Casting-cold extrusion technology was presented to fabricate aluminum/copper clad composite,and copper tubes with different sketch sections were designed.The technology of aluminum/copper clad composite fabricated by casting-cold extrusion was simulated by DEFORM software using tubes with four arc grooves.The stress and strain in different deformation zones were analyzed.The groove size reduces gradually and the groove shape drives to triangle during the extrusion procedure.The maximum values of equivalent effective stress and radial stress appear in groove zones,and the maximum equivalent effective strain firstly is obtained also in groove zones.The grain size in groove zones is less than that in other zones.The experimental results are consistent with simulation results,which prove that the copper tubes with sketch section are favorable to the metallurgy bond of boundary interface between aluminum and copper.展开更多
A direct electroless copper （Cu） coating on tungsten powders method requiring no surface treatment or stabilizing agent and using glyoxylic acid （C2H203） as a reducing agent was reported. The effects of copper sul...A direct electroless copper （Cu） coating on tungsten powders method requiring no surface treatment or stabilizing agent and using glyoxylic acid （C2H203） as a reducing agent was reported. The effects of copper sulfate concentration and the pH of the plating solution on the properties of the prepared W@Cu composite powders were assessed. The content of Cu in the composite powders was controlled by adjusting the concentration of copper sulfate in the electroless plating solution. A uniform, dense, and consistent Cu coating was obtained under the established optimum conditions （flow rate of C2H203 = 5.01 mL/min, solution pH = 12.25 and reaction temperature 45.35℃） by using central composite design method. In addition, the crystalline Cu coating was evenly dispersed within the W@Cu composite powders and Cu element in the coating existed as Cu~. The formation mechanism for the W@Cu composite powders by electroless plating in the absence of surface treatment and stabilizing agent was also proposed.展开更多
Al2O3 short fiber reinforced La-bearing Al-5%Cu alloy was fabricated by squeeze casting,and the solidified structure and the solute segregation during alloy solidification were studied.The results indicated that La ha...Al2O3 short fiber reinforced La-bearing Al-5%Cu alloy was fabricated by squeeze casting,and the solidified structure and the solute segregation during alloy solidification were studied.The results indicated that La has been enriched near the interface which is favorable to improve the wettability between the fiber and Al alloy,but the RE-rich phase was not formed at the interface.At the end of the solidification of the composites,the change of the solute in the surplus liquid phase results in the type of matrix alloy being changed because of the selective crystallization,and the segregation at the interface is finally formed.There is no special influence by La on the Cu segregation in the matrix alloy.展开更多
文摘Casting-cold extrusion technology was presented to fabricate aluminum/copper clad composite,and copper tubes with different sketch sections were designed.The technology of aluminum/copper clad composite fabricated by casting-cold extrusion was simulated by DEFORM software using tubes with four arc grooves.The stress and strain in different deformation zones were analyzed.The groove size reduces gradually and the groove shape drives to triangle during the extrusion procedure.The maximum values of equivalent effective stress and radial stress appear in groove zones,and the maximum equivalent effective strain firstly is obtained also in groove zones.The grain size in groove zones is less than that in other zones.The experimental results are consistent with simulation results,which prove that the copper tubes with sketch section are favorable to the metallurgy bond of boundary interface between aluminum and copper.
基金Funded by the National Natural Science Foundation of China(Nos.51202175 and 11072228)the National 111 Project(No.B13035)
文摘A direct electroless copper （Cu） coating on tungsten powders method requiring no surface treatment or stabilizing agent and using glyoxylic acid （C2H203） as a reducing agent was reported. The effects of copper sulfate concentration and the pH of the plating solution on the properties of the prepared W@Cu composite powders were assessed. The content of Cu in the composite powders was controlled by adjusting the concentration of copper sulfate in the electroless plating solution. A uniform, dense, and consistent Cu coating was obtained under the established optimum conditions （flow rate of C2H203 = 5.01 mL/min, solution pH = 12.25 and reaction temperature 45.35℃） by using central composite design method. In addition, the crystalline Cu coating was evenly dispersed within the W@Cu composite powders and Cu element in the coating existed as Cu~. The formation mechanism for the W@Cu composite powders by electroless plating in the absence of surface treatment and stabilizing agent was also proposed.
基金the National Key R&D Program of China(No.2018YFA0707300)the National Natural Science Foundation of China(Nos.51904206,52105390,51905372,51805359)+3 种基金the China Postdoctoral Science Foundation(No.2020M670705)the Natural Science Foundation of Shanxi Province,China(No.201801D221130)the Major Program of National Natural Science Foundation of China(No.U1710254)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi Province,China(No.2019L0258).
基金The study is supported by the Key Research Program of the Ministry of National Education(Authorized No.:00191)the Natural Science Foundation of Jiangxi Province(Authorized No.:0150032).
文摘Al2O3 short fiber reinforced La-bearing Al-5%Cu alloy was fabricated by squeeze casting,and the solidified structure and the solute segregation during alloy solidification were studied.The results indicated that La has been enriched near the interface which is favorable to improve the wettability between the fiber and Al alloy,but the RE-rich phase was not formed at the interface.At the end of the solidification of the composites,the change of the solute in the surplus liquid phase results in the type of matrix alloy being changed because of the selective crystallization,and the segregation at the interface is finally formed.There is no special influence by La on the Cu segregation in the matrix alloy.
基金financially supported by the Special Funds of National Ministry of Finance for the Transformation of Industrial Technology Achievements (No.CJ2007-475)
