原位自生纳米Al2O3/Al-Zn-Cu复合材料的力学性能

将纳米ZnO粉末和Al粉球磨后冷压成Al-ZnO预制块,然后将其加到Al-Zn-Cu熔体中进行Al-ZnO原位反应,制备出纳米Al₂O₃颗粒增强Al-Zn-Cu基复合材料。能谱面扫描分析和透射电镜观察结果表明,复合材料由纳米Al₂O₃颗粒和Al₂Cu析出相两种颗粒/析出相组成。纳米Al₂O₃颗粒通过异质形核和晶界钉扎,细化了Al-Zn-Cu合金晶粒组织和Al₂Cu析出相。原位纳米Al₂O₃颗粒的生成提高了基体合金的拉伸性能,轧制+热处理使Al₂O₃/Al-Zn-Cu复合材料的拉伸强度比相同处理的基体合金提高约100%,总伸长率提高约98%。

Mechanical Properties of In-situ Synthesised Nano Al2O3/Al-Zn-Cu Composites

Nano Al₂O₃ particles reinforced Al-Zn-Cu alloy composite of Al₂O₃/Al-Zn-Cu was prepared by a two-step process, namely nano-ZnO powder and Al powder were first ball-milled and then cold-pressed to prepare Al-ZnO preforms, and next which was added to the stirring Al-Zn-Cu melt, thereby nano Al₂O₃ particles reinforced Al-Zn-Cu based composites were prepared through Al-ZnO in-situ reaction. The results of energy spectrum scan and transmission electron microscope show that there are mainly two kinds of particles/precipitated phases in the composite material: nano Al₂O₃ particles and Al₂Cu precipitated phases. The grain structure and precipitates of Al-Zn-Cu alloy were refined by nano-sized Al₂O₃ particles through the heterogeneous nucleation and grain boundary pinning. The formation of in-situ nano Al₂O₃ particles could enhance the tensile properties of the base alloy. After proper rolling + heat treatment the Al₂O₃/Al-Zn-Cu composites present tensile strength and total elongation percentage ca 100% and 98% higher than that of the Al-Zn-Cu matrix alloy equally treated, respectively.