原位自生纳米Al_(2)O_(3)/Al-Zn-Cu复合材料的力学性能

Mechanical Properties of In-situ Synthesised Nano Al_(2)O_(3)/Al-Zn-Cu Composites

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Al_(2)O_(3)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Al_(2)O_(3)颗粒和Al_(2)Cu析出相两种颗粒/析出相组成。纳米Al_(2)O_(3)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Al_(2)Cu析出相。原位纳米Al_(2)O_(3)颗粒的生成提高了基体合金的拉伸性能,轧制+热处理使Al_(2)O_(3)/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%。

Nano Al_(2)O_(3) particles reinforced Al-Zn-Cu alloy composite of Al_(2)O_(3)/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 Al_(2)O_(3) particles reinforced Al-Zn-Cu based composites were prepared through Al-ZnO in-situ reac-tion.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 Al_(2)O_(3) particles and Al_(2)Cu precipitated phases.The grain structure and precipitates of Al-Zn-Cu alloy were refined by nano-sized Al_(2)O_(3) particles through the heterogeneous nucleation and grain boundary pinning.The formation of in-situ nano Al_(2)O_(3) particles could enhance the tensile properties of the base alloy.After proper rolling+heat treatment the Al_(2)O_(3)/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.