中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 30 No. 11 November 2020 |
（1. Department of Materials Science and Engineering, Sahand University of Technology, P. O. Box 51335-1996, Tabriz, Iran;
2. Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran）
Abstract:Given the nonuse of TiO2 nanoparticles as the reinforcement of AA2024 alloy in fabricating composites by ex-situ casting methods, it was decided to process the AA2024-xTiO2(np) (x=0, 0.5 and 1 vol.%) nanocomposites by employing the stir casting method. The structural properties of the produced samples were then investigated by optical microscopy and scanning electron microscopy; their mechanical properties were also addressed by hardness and tensile tests. The results showed that adding 1 vol.% TiO2 nanoparticles reduced the grain size and dendrite arm spacing by about 66% and 31%, respectively. Also, hardness, ultimate tensile strength, yield strength, and elongation of AA2024- 1vol.%TiO2(np) composite were increased by about 25%, 28%, 4% and 163%, respectively, as compared to those of the monolithic component. The agglomerations of nanoparticles in the structure of nanocomposites were found to be a factor weakening the strength against the strengthening mechanisms. Some agglomerations of nanoparticles in the matrix were detected on the fractured surfaces of the tension test specimens.
Key words: AA2024-TiO2 nanocomposites; mechanical properties; microstructure; fracture surface; stir casting process
