Study On Effects Of Ceramic-matal Interface To Properties Of Al₂O₃Dispersion Strengthened Copper

Alumina dispersion strengthened copper material has the characteristics ofhigh strength, high conductivity and high thermal stability, made it used inresistance spot welding, machinery manufacturing, electronic appliances and otherfields widely. In this paper, dispersion strengthened copper was prepared bymechanical alloying, to obtains dispersion strengthened copper bars by hotextrusion. We mainly focus contents as followed:Study on preparing dispersion strengthened copper by mechanical alloyingwhich use ex-situ and in-situ synthesis methods, get the conclusion that aluminacan achieve complete solid solution and dispersion distribution only in10h highenergy ball milling by use in-situ method, because alumina particles were in-situproducts of mechanical alloying process and have the feathers of better wettability,higher combine strength, better compatibility, which make them forms a stableinterface structure with copper matrix in a short period time.Annealing the dispersion strengthened copper powders after mechanicalalloying, compare the effects of Ag doping and synthesis process on the aluminadispersoids’ thermal stability. After annealing in high temperature, aluminadispersoids in dispersion strengthened copper which prepared by ex-situ synthesiswith Ag doping have a better thermal stability and rarely grow up, indicates Aginhibits the growth of dispersoids; Alumina dispersoids prepared by in-situsynthesis also have the a better thermal stability and growth up is not obvious afterannealing, indicates alumina is stable prepared by in-situ synthesis.Obtain dispersion strengthened copper bars by mould pressing, sintering andhot extrusion, measure density, hardness, strengthened, soften temperature andconductivity. Get the conclusion that Ag doping can improve the mechanicalproperties of the material, in-situ synthesis method is better than ex-situ synthesismethod to improve the mechanical properties.Ag doping can improve material properties by increasing metal-ceramicinterfacial work of separation and inhibiting the segregation of alumina dispersoidsto metal-ceramic interface; in-situ synthesis method improved material propertiesby enhancing combine degree and wettability of alumina and copper matrix. Theprinciple of improving material performances is achieved by fine-grainedstrengthening and dispersion strengthening.The soften temperature of dispersion strengthened copper higher than950℃,very close to the melting point of copper; dispersion strengthened copper prepared by in-situ synthesis method which doped with Ag has hardness of86.77HRB andtensile strength of481.77MPa.