Nano-ceramic particles are generally difficult to add into molten metal because of poor wettability. Nano-SiCParticles reinforced A356 aluminum alloy composites were prepared by a new complex process, i.e., a molten-metal process combined with high energy ball milling and ultrasonic vibration methods. The nano particles were β-SiCP with an average diameter of 40 nm, and pre-oxidized at about 850 °C to form an oxide layer with a thickness of approximately 3 nm. The mm-sized composite granules containing nano-SiCP were fi rstly produced by milling the mixture of oxidized nano-SiCP and pure Al powders, and then were remelted in the matrix-metal melt with mechanical stirring and treated by ultrasonic vibration to prepare the composite. SEM analysis results show that the nano-SiCP articles are distributed uniformly in the matrix and no serious agglomeration is observed. The tensile strength and elongation of the composite with 2 wt.% nano-SiCP in as-cast state are 226 MPa and 5.5%, improved by 20% and 44%, respectively, compared with the A356 alloy.
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