残余形变对莫来石短纤维/Al-4.5Cu复合材料及其基体合金时效析出行为的影响

用挤压铸造法制备莫来石(mullite)短纤维/Al-4.5Cu复合材料及其基体合金。用硬度测试(HB)、差示扫描量热仪(DSC)和透射电镜(TEM),研究固溶淬火后残余形变(0 %,12.5 %,25 %,34.4%)和纤维对复合材料及其基体合金时效析出行为的影响。结果表明:形变对Al-4.5Cu合金的时效析出过程具有十分明显的加速作用,随着形变度增加,时效加速作用进一步加强;莫来石短纤维对Al-4.5Cu合金的时效析出过程具有加速作用;纤维和形变同时存在时,复合材料的时效析出过程还会进一步加快。但是,形变或/和纤维抑制了Al-4.5Cu合金中GP区的形成。

EFFECT OF RETAINED DEFORMATION ON THE AGE-PRECIPITATION BEHAVIOUR OF Mullite/Al-4.5Cu COMPOSITE AND ITS MONOLITHIC ALLOY

Short mullite fiber reinforced Al-4.5Cu composite and its monolithic alloy were produced by squeeze casting. The effect of the retained deformation made afterice-water quench with 0%,12.5%,25% or 34.4% and/or that of the fibers fabricated well with the matrix on the age-precipitation behaviour of the testing materials have been investigated by means of hardness measurement (HB),differential scanning calorimetry (DSC) and transmission electron microscope (TEM),respectively. The results indicate that the retained deformation considerably accelerates the ageing response of Al-4.5Cu alloy and the effect of precipitation acceleration is further promoted with increasing the deformation degree. Short mullite fibers also accelerate the ageing response of Al-4.5Cu alloy. Moreover,the age-precipitation progress of the testing composite is further accelerated when there exist both of the fiber and the deformation. The GP zone formation is, however,suppressed due to the introduction of retained deformation and/or short mullite fibers.