Al72Ni12Co16准晶颗粒/铝基复合材料中的相转变及其力学性能

Phase Transition and Mechanical Properties of Al-Based Composites Reinforced by Al72Ni12Co16 Decagonal Quasicrystalline Particles

摘要:

以Al72Ni12Co16单相十次准晶为增强颗粒、纯铝和Al-5.5%Zn（质量分数，下同）为基体制备铝基复合材料。采用扫描电镜和能谱分析复合材料的微观组织和颗粒分布情况。结果表明，准晶颗粒在熔体中热稳定性差而发生相转变。θ相呈规则的多变形状分布于Al基体中，颗粒尺寸主要在3.45~40 μm范围内分布；与此同时，晶界处还会形成细小的长条状γ相，其尺寸为1.15~8.57 μm。力学性能结果表明，最终形成的晶化相有助于提高复合材料的屈服强度、抗拉强度和弹性模量，而延伸率则急剧降低。

Abstract:

Aluminum-based composites, using Al72Ni12Co16 decagonal quasicrystalline as reinforcing particles and pure Al and Al-5.5%Zn alloys (mass fraction) as base alloy, were fabricated. The microstructure and the particle distribution of the composite were analyzed by scanning electron microscopy (SEM) and energy dispersive spectrum (EDS). Results show that the phase transition occurs because the decagonal quaicrystalline particles are unstable in the melt. Regular polygon-like θ-phase distributes in the Al matrix, with particle sizes mainly ranging from 3.45-40 μm. At the same time, fine strip-like γ-phase with the size of 1.15-8.57 μm are formed along the grain boundaries. Mechanical property testing results reveal that, due to the existence of the final crystallized phases, yield strength, ultimate tensile strength and Young’s modulus of the composites are improved, but the elongation is decreased rapidly.