Al-Cu-Fe-Cr准晶增强铝基复合材料的研究

Study on Al-Cu-Fe-Cr Quasicrystalline Reinforced Aluminum Matrix Composites

采用常规铸造法制备了四元系Al-Cu-Fe-Cr准晶,利用XRD、SEM和TEM等分析手段,分析了准晶和其类似相的微观组织以及在热处理后的相转变。以ZL101合金为基体,Al-Cu-Fe-Cr准晶颗粒为增强体,通过机械搅拌的方法制备了Al-Cu-FeCr准晶/ZL101复合材料,分析复合材料的微观组织和成分,并研究其力学性能。结果表明:铸态准晶合金组织中含有Al65Cu20-Fe10Cr5相(I+d)、准晶I相、λ-Al3Fe相以及少量的η-AlCu和θ-Al2Cu相,经880℃×30min热处理水淬后,λ相消失,得到了高纯度的Al65Cu20Fe10Cr5相和准晶I相;复合材料中由于准晶和基体之间的相互扩散,使得准晶相失稳发生分解;随着准晶含量的增加,复合材料的抗拉强度增加,延伸率减小,但由于Cr元素的加入使针状的β-Fe相转变成汉字状或骨骼状的α-Fe相,对复合材料的延伸率有提升作用。

The Al-Cu-Fe-Cr quasicrystalline were prepared by conventional casting method.The microstructures and the phase transition after heat treatment of quasicrystalline and other similar phases were characterisied by XRD,SEM and TEM.The aluminium-based composites were fabricated by using the Al-Cu-Fe-Cr quasicrystalline particles as reinforcing phase and ZL101 as matrix with mechanical stirring.The microstructures and compositions of the composites were analyzed and its mechanical properties were studied.The results show that the as-cast quasicrystalline material was composed of Al65 Cu20 Fe10 Cr5（I＋d）,quasicrystalline I,λ-Al3 Fe,and a small amount ofη-AlCu,θ-Al2 Cu phases,after heat treatment at 800 ℃ for 6 h,λphase trend to transform into I phase.In the composite material,the diffusion between the quasicrystalline and the matrix alloy caused the decomposition of the structure of quasicrystalline phase.With the increase of quasicrystalline content,the tensile strength of the composites increased and the elongation decreased.However,the addition of the Cr element changed the acicularβ-Fe phase into a Chinese character-like or bone-likeα-Fe phase which increased the elongation of the composite.