单相或混杂颗粒增强铝基复合材料的原位制备技术

In-situ Fabrication Technique of Al-matrix Composites Reinforced with Single or Hybrid Particles

以TiB_2/Al及TiB_2+Mg_2Si/Al铝基复合材料为例,探讨单相或混杂颗粒增强铝基复合材料的原位制备技术及混杂增强的优势。结合混合盐反应法与熔铸法成功地制备出体积分数5%TiB_2+10%Mg_2Si/Al混杂颗粒增强复合材料,并对其进行组织分析和性能检测。结果表明:TiB_2颗粒能够作为Mg_2Si相的优质异质形核基底从而有效地细化并均匀化Mg_2Si相,Mg_2Si共晶胞尺寸从50μm细化至10μm以下;在晶界区域团聚的TiB_2颗粒被Mg_2Si相打散而较均匀地分布,二者形成相互优化趋势;TiB_2+Mg_2Si/Al的屈服强度和抗拉强度较TiB_2/Al分别提升了88%和45%。

Taken the composites of TiB 2/Al and TiB 2＋Mg 2Si/Al Al-matrix as examples in this paper, the in-situ fabrication techniques of Al-matrix composites reinforced with single or hybrid particles and the advantages of hybrid reinforcement are investigated. The salt-metal reaction route and melting process were combined to fabricate 5vol% TiB 2＋10% Mg 2Si/Al composites successfully. Microstructure analysis and performance testing were carried out, and the results showed that,the TiB 2 particles can act as good heterogeneous nucleation site for Mg 2Si phase, which leads to the refinement and uniform distribution of Mg 2Si. The Mg 2Si eutectic phase is refined from over 50 μm to under 10 μm. TiB 2 particles gathered along the grain boundary are broken up by Mg 2Si phase, and TiB 2 particles are uniformly distributed. The mutual refinement of TiB 2 particles and Mg 2Si phase is discovered. Compared with TiB 2/Al composite, the yield stress and ultimate tensile strength of TiB 2＋Mg 2Si/Al composite are improved by 88% and 45%, respectively.