ABSTRACT

The effect of Sc-microalloying and Y₂O₃ nano-particles on the microstructure and mechanical properties of as-cast Al-5.5Si alloy is studied by means of optical microscopy, transmission electron microscopy, hardness test and tensile test. The influence of annealing treatment on the microstructure and properties of the Al-Si alloys is also investigated as well. The results show that the addition of Sc and Y₂O₃ nano-particles could significantly improve the mechanical property of the Al-Si alloy. The ultimate tensile strength and yield strength of Al-Si-Sc/Y₂O₃ alloy are improved by around 45 and 71%, respectively, when compared to that of the Al-Si alloy. The effect of the nanosized particles (precipitated and added) on strengthening and deformation of Al-Si alloy is analyzed and discussed in detail. The results of annealing treatment indicate that the change in mechanical property of the Al-Si-Sc alloy during annealing treatment is mainly associated with the precipitation of the secondary Si phase.

摘要

通过光学显微镜，透射电子显微镜，硬度试验和拉伸试验研究了Sc微合金化和Y ₂ O ₃纳米颗粒对铸态Al-5.5Si合金组织和力学性能的影响。还研究了退火处理对Al-Si合金的组织和性能的影响。结果表明，Sc和Y ₂ O ₃纳米粒子的添加可以显着改善Al-Si合金的力学性能。Al-Si-Sc / Y ₂ O ₃的极限抗拉强度和屈服强度与Al-Si合金相比，该合金分别提高了约45％和71％。分析和讨论了纳米颗粒（沉淀和添加）对Al-Si合金强化和变形的影响。退火处理的结果表明，Al-Si-Sc合金在退火处理过程中的机械性能变化主要与次级Si相的析出有关。