Preparation Of Al₂O₃/Cu Composites By Internal Oxidation And Properties Study

Copper matrix composites reinforced with oxide particles have been widely used as electrode material,contact material,integrated circuit lead frame because they have high strength,high electrical conductivity,excellent high temperature properties, and so on.In this paper,Al₂O₃/Cu composites were prepared by the combination methods of MA and IN-SITU.The technology to prepare Cu-Al alloy based on Cu by high energy ball milling was discussed.Technique parameters of the internal oxidation and the affection to the microstructures and properties of Al₂O₃/Cu composites have been studied.The following were some meaningful results;(1)One effective way to prepare powders of Cu-Al alloy by high energy ball milling has been proposed.As the density of Al and Cu was quite difference,it was apt to delaminate and restrain the process of alloy by wet milling.The case was improved when dry milling,though it would be some reunite with the time of ball-milling prolonging.(2)The best technique parameters of high energy ball milling to prepare metastable powders of Cu-Al alloy were;the addition of Al powders was 1% in quality,the powders of Cu-Al were completely alloyed after high energy ball milling for 20 h.(3)The best technique parameters of internal oxidation are suggested;the ratio of Cu₂O to Al is 6;1 in quality,the pressure is 750 MPa,the temperature is 1050℃for 4h.It was completely able to prepare Al₂O₃/Cu composition reinforced with oxide particles,the size of Al₂O₃ was about 100 nm.(4)The condition which the internal oxidation reaction of Cu-Al alloy can take place has been studied and corresponding technique parameters have been set on the basis of theoretical analyze.In the view of thermodynamics,the oxygen should be about;The top limit oxygen partial pressure is very small,it is proportional with temperature.So we can increase temperature to reduce the difficulty of controlling in real process.The lower limit oxygen partial pressure is also very small,it can be omitted in real process.At the same time,the temperature of Cu-Al alloy IN-SITU range from 1107K to 1320K.Among this temperature range,oxygen partial pressure is easy to control and Cu₂O will decompose and release oxygen.