Al-Cu-Co十次准晶颗粒增强铝基复合材料的微观组织和制备中的相转变

Microstructures and Phase Transformation of Al-Based Composite Materials Reinforced by Al-Cu-Co Decagonal Quasicrystalline Particles

摘要:

采用电弧炉熔炼配置成分为Al65Cu15Co20十次准晶合金锭，并以Al65Cu15Co20准晶颗粒为增强相，Al-4.5%Cu合金为基体，采用熔体机械搅拌法制备准晶颗粒增强铝基复合材料。利用XRD、SEM及EDS分析Al65Cu15Co20准晶合金及颗粒增强铝基复合材料的相成分、微观组织及各组成相的分布，并详细分析准晶颗粒加入熔体前后的形貌、相成分和结构的变化。由于准晶颗粒与熔体之间的相互扩散作用，使得准晶颗粒加入熔体后迅速失稳，其形貌则由加入前的不规则多边形状转变成块状和板条状，并发生如下相转变：D-Al62.10Cu17.46Co20.44→θ-Al79.58Cu1.10Co19.32，在随后的凝固过程中，由于“界面推移效应”使得θ相沿晶界处均匀分布

Abstract:

Al65Cu15Co20 decagonal quasicrystalline alloys were prepared by an arc-melting furnace. The aluminium-based composites were fabricated by using the Al65Cu15Co20 decagonal quasicrystalline particles as reinforcing phase and Al-4.5 wt%Cu alloy as matrix with mechanical stirring. The microstructures, the phase composition, and the distribution of Al65Cu15Co20 were characterisied by XRD, SEM, SEM and EDS for the Al65Cu15Co20 quasicrystalline alloys and the reinforced composites. And the morphology, chemical composition and structure changes of the quasicrystalline particles before and after adding to the melt were also analysised. As the interdiffusion occurs between the quasicrystalline particles and the melt, the quasicrystalline particles can not exist stably in the melt. The morphology of the particles turns from inregular polygons to block and lath-like in shape as following: D-Al62.10Cu17.46Co20.44 → θ-Al79.58Cu1.10Co19.32 after adding the quasicrystalline particles into the melt. During the solidification process, the θ phase distributes uniformly along the grain boundaries because of the “interfacial pushing effect”