准晶增强铝基复合材料的微观组织及热膨胀行为

Microstructure and Thermal Expansion Behavior of Al-based Composite Reinforced by Al-Ni-Co Quasicrystal Particles

以铝粉(+200目)为基体、准晶颗粒(粒度≤30μm)为增强相,采用粉末冶金法制备了准晶颗粒增强铝基复合材料。采用光学显微镜、扫描电镜、能谱分析仪分析了该复合材料的微观组织及界面结合特征,并用TMA设备研究了复合材料在25～500℃的热膨胀行为。XRD和SEM分析结果均证明准晶具有良好的结构和热稳定性。准晶颗粒与Al基体之间存在成分均匀且界面厚度均匀的过渡层(厚度<1μm),且准晶颗粒在Al基体内均匀分布。TMA结果表明:颗粒尺寸对复合材料的热膨胀系数影响最为显著,当颗粒尺寸为10～30μm时,其线膨胀系数达到最小值16.25×10-6/℃;复合材料的热膨胀系数随着颗粒含量的增加而减小。

Taking Al powder（＋200 mesh） and Al72Ni12Co16 decagonal quasicrystal powders（≤30 μm） as strengthen phase,the Al-base composite was fabricated using powder metallurgical method.The microstructure and interface bond characteristic of composite were analyzed using OM,SEM and EDS.The thermal expansion of the composite at 25 ℃～500 ℃was also investigated using TMA equipment.The XRD and SEM results show that the quasicrystal has good structure and stability after sintering.Microstructural observation shows that uniform interfacial layer between the quasicrystal and Al matrix can be obtained,and the quasicrystal particles were uniformly distributed in the microstructure.The TMA results show that the particle size plays a key role of the thermal expansion of the composite,and it reaches the minimum value with 16.25 × 10-6 /℃.As the particle content increases,the thermal expansion of the composite increases.