摘要:
研究了一种新型简化内氧化工艺制备Cu-Al2O3复合材料烧结过程中的致密化和内氧化。结果表明,混合粉末压制成形后的压坯密度随烧结时间延长而增加,经950℃烧结8 h后稳定在7.96 g/cm3左右,较烧结前密度增幅达4.3%;同时Cu-Al合金颗粒完成了内氧化,生成了大量粒状的Al2O3并弥散分布于铜基体,其粒径约为520 nm,颗粒间距约为25~60 nm。理论计算表明,当Cu-Al合金颗粒间孔隙直径小于27.5μm时,粉末压坯发生收缩,密度增加;当孔隙直径大于27.5μm时,压坯发生膨胀,密度降低。实际上密度的变化是收缩和膨胀两种效应综合作用的结果。
关键词:
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Cu-Al合金
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烧结
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致密化
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内氧化
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孔隙
Abstract:
Densification and internal oxidation during sintering process in preparation of Cu-Al2O3 composite with a new simpli-fied internal oxidation technique were investigated.The results show that as the sintering goes on,the density of the pressing mixed powder blank increases and is stabilized at 7.96g/cm3 after sintering at 950℃for 4 hours,which increases by 4.3% com-pared with unsintered blank at the same time,and internal oxidation of Cu-Al alloy particles ocnurs.A mass of fine Al2O3 parti-cles are dispersed in the copper base,the size of Al2O3 particles is about 1020 nm in diameter,and the spatial distance between particles is about 2560 nm.Theoretical analysis indicates that the blank will shrink and its density will increase when the di-ameter of pore is smaller than 27.5μm,on the contrary,it will expand and the density will decrease when the diameter of pore is bigger than 27.5μm.The variation of density is caused by the effects of shrinkage and expansion.
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