Al63+xCu25-xFe12（x=0,1）准晶增强ZL101的实验和计算研究

Al-Cu-Fe quasicrystal has attracted much attention by the advantages of high strength, good wetting property and a series of excellent properties. It is an ideal reinforcement, but it often appears similar phase in its preparation process. So obtaining the single component of quasicrystal is not easy; and because of the high temperature in the preparation of quasicrystal reinforced aluminum matrix composites, that is easy to cause the quasicrystal composition changing and "disappeared". At the same time, because the quasicrystal has no specific crystal structures, limiting the research of scale and scope. This project prepared the Al63+xCu25-xFe12 (x=0,1) quasicrystals of single ingredients for reducing the interference of its similar phase, by controling the pouring temperature, the heating temperature, holding time and other process parameters. We have adoptted the method of “preformed unit + squeezing casting” to prepare Al63+xCu25-xFe12 (x=0,1) quasicrystal reinforced ZL101 matrix composite material, which can reserve original component of quasicrystal. Al-Cu-Fe quasicrystal without a clear crystal structure disposed by “similar phase structural similarity” that will make the research of quasicrystal in atom scale, and analyze the thermodynamic and mechanical properties at the atomic level and combine with experimental research, which is expected to provide a new research design idea of metal matrix composites for quasicrystal and its enhancement.

Al-Cu-Fe准晶因具有强度高、润湿性好等一系列优异性能而备受关注，是一种理想的增强体，但在制备过程中常出现类似相，不易获得单一成分的准晶；并且，在制备准晶增强铝基复合材料时，由于温度高而易导致准晶成分改变乃至“消失”等问题；且由于准晶不具有特定的晶体结构，限制了其研究尺度和范围。本项目拟通过控制浇注温度、加热温度、保温时间等工艺参数，制备出成分趋于单一化的Al63+xCu25-xFe12（x=0,1）准晶，减少类似相的干扰；采用“预制件+挤压铸造”法制备Al63+xCu25-xFe12（x=0,1）准晶增强ZL101基复合材料，可有效地保留准晶成分；将不具有明确晶体结构的Al-Cu-Fe准晶通过“类似相的结构相似性”处理，使得对准晶的研究工作可以建立在原子尺度上，在原子层次上分析其热力学和力学性质，并与实验研究相结合，为准晶及其增强金属基复合材料设计提供了一种新的研究思路。

铝基准晶颗粒不仅具有高硬度、高弹性模量、高热力学稳定性、低表面能等特性，而且铝基准晶与铝合金的润湿性非常好，界面结合强度高。因此，在本项目中用铝基准晶颗粒作为铝基复合材料的增强体。在本项目中，采用常规铸造法，通过成分优化、控制冷却速度和热处理工艺，获得了单一成分的Al63+xCu25-xFe12（x=0,1）准晶相的制备工艺；并以该工艺制备了Al-Cu-Fe-Cr准晶，其为十次准晶相和二十面体准晶相的混合物；依据准晶和其类似相的结构特点，构造Al64Cu24Fe12的晶体结构，并研究了其电子性质。以铝铜铁准晶为强化相，以ZL101合金为基体，通过挤压铸造工艺制备了准晶增强铝基复合材料。研究表明，(Al63Cu25Fe12)p/ZL101与(Al64Cu24Fe12)p/ZL101复合材料的抗拉强度、延伸率和硬度并无明显区别。因而，Al63Cu25Fe12和Al64Cu24Fe12具有相似的强化效果。准晶的晶粒度为200目-100目时具有最佳的强化效果。复合材料的抗拉强度随着准晶加入量的增多呈现逐渐增大的趋势；与AlCuFe准晶增强ZL101复合材料相比，AlCuFeCr增强ZL101复合材料的综合性能较低。因而Al-Cu-Fe-Cr的增强效果不如AlCuFe准晶。此外，准晶增强ZL101复合材料的强度、硬度、延伸率和流动性均高于SiC增强ZL101复合材料。因而，AlCuFe准晶更适合作为ZL101的外加增强相，制备的铝基复合材料可应用于汽车和航空航天领域。