Effect of mechanical alloying time and rotation speed onevolution of CNTs/Al-2024 composite powders
(1. Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education,
School of Materials Science and Engineering, Beihang University, Beijing 100191, China;
2. Department of Mechanical Engineering, Faculty of Science and Engineering, Ritsumeikan University,
1-1-1Nojihigashi, Kusatsu, Shiga 525-8577, Japan)
School of Materials Science and Engineering, Beihang University, Beijing 100191, China;
2. Department of Mechanical Engineering, Faculty of Science and Engineering, Ritsumeikan University,
1-1-1Nojihigashi, Kusatsu, Shiga 525-8577, Japan)
Abstract: Carbon nanotubes (CNTs) reinforced aluminum matrix composites were fabricated by mechanical milling followed by hot extrusion. The commercial Al-2024 alloy with 1% CNTs was milled under various ball milling conditions. Microstructure evolution and mechanical properties of the milled powder and consolidated bulk materials were examined by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and mechanical test. The effect of CNTs concentration and milling time on the microstructure of the CNTs/Al-2024 composites was studied. Based on the structural observation, the formation behavior of nanostructure in ball milled powder was discussed. The results show that the increment in the milling time and ration speed, for a fixed amount of CNTs, causes a reduction of the particle size of powders resulting from MM. The finest particle size was obtained after 15 h of milling. Moreover, the composite had an increase in tensile strength due to the small amount of CNTs addition.
Key words: CNTs; Al matrix composite; mechanical milling; microstructure