中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
Vol. 23 No. 5 May 2013 |
(1. Department of Materials Science and Metallurgical Engineering, Engineering Faculty,Ferdowsi University of Mashhad, Mashhad, Iran;2. Department of Materials Science and Metallurgical Engineering, Engineering Faculty,Semnan University of Semnan, Semnan, Iran)
Abstract:A novel two step mixing method including injection of particles into the melt by inert gas and stirring was used to prepare aluminum matrix composites (AMCs) reinforced with Al2O3 particles. Different mass fractions of micro alumina particles were injected into the melt under stirring speed of 300 r/min. Then the samples were extruded with ratios of 1.77 or 1.56. The microstructure observation showed that application of the injection and extrusion processes led to a uniform distribution of particles in the matrix. The density measurements showed that the porosity in the composites increased with increasing the mass fraction of Al2O3 and stirring speed and decreased by extrusion process. Hardness, yield and ultimate tensile strengths of the extruded composites increased with increasing the particle mass fraction to 7%, while for the composites without extrusion they increased with particle mass fraction to 5%.
Key words: Al/Al2O3 composite; stir-casting; extrusion; microstructure; mechanical properties