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用差示扫描量热仪 (DSC)和透射电镜 (TEM)对莫来石 (Mullite)短纤维增强Al 4 .5Cu复合材料及其基体合金的时效析出行为进行了研究。结果表明 :淬火态复合材料界面附近基体一侧中存在高密度位错 ;复合材料DSC曲线低温段GP区的形成和溶解被严重推延和抑制 ,而中高温段θ″和θ′相的析出则明显快于基体合金 ;190℃时效时 ,复合材料DSC曲线上θ′相析出放热峰随时效时间的增加而快速衰退 ,而基体合金DSC曲线上θ′相析出放热峰衰退相对较慢 ,表明纤维对θ′相的析出具有明显的加速作用。TEM研究表明 :同一时效条件下 ,θ′相在复合材料中的析出数量较多、尺寸较大 ,θ′相与Al基体有良好的晶体学共格关系。
The precipitation behavior of Mullite short fiber reinforced Al 4 .5Cu composites and their matrix alloys was investigated by differential scanning calorimetry (DSC) and transmission electron microscopy (TEM). The results show that there are high density dislocations in the matrix near the interface of the quenched composites. The formation and dissolution of the GP region in the low temperature section of the composites are seriously delayed and suppressed. However, the precipitation of θ "and θ ’ Which is obviously faster than that of the matrix alloy. At 190 ℃, the exothermic peak of the θ ’phase precipitates rapidly decayed with the increase of the aging time. However, the exothermic peak of the θ’ phase of the DSC curve of the matrix alloy declines relatively slowly, It is shown that the fiber accelerates the precipitation of θ ’phase.The TEM study shows that θ’ phase has more precipitation and larger size in the composite under the same aging condition, and the θ ’phase has a good crystal with the Al matrix Learn a coherent relationship.