A Method for the Production of Large Sized AI-B_4C-Al_2O_(3np) Nanocomposites through Liquid-State Process

摘要

The paper introduces a new method to produce large sized AI-B_4C-Al_2O_(3np) composites, which combines ball milling to prepare Al_2O_(3np)/Al mixed powder and semi-solid casting to contribute the injection of Al_2O_(3np)/Al mixed powder into the melt. The deformation performance of Al_2O_(3np) and micro-Al through ball milling with different Al/Al_2O_(3np) ratios, different milling time and different balls were studied respectively. It was revealed that micro-Al particles were milled from twisted and crimpled foil pieces to shuttles with Al_2O_(3np) embedded on it through 4h milling with 10mm balls. And we consider it as the best bonding between Al_2O_(3np) and micro-Al we could attain. And a plate of 25kg of AI-B_4C-Al_2O_(3np) composite was fabricated successfully with the injection of the Al_2O_(3np)/Al mixed powder. Spherical Al_2O_(3np) of 300nm and needle-like TiB_2 with 200nm in radius and 800nm-4μm in length were found in SEM photographs. Tensile properties of AI-B_4C-Al_2O_(3np) composites were tested at room temperature and high temperature. It was showed higher mechanical properties than Al-B_4C composites at room temperature and elevated temperature. Particularly, a 40% increase of UTS of Al-15wt.% B_4C-lwt.%Al_2O_(3np) at 350°C was observed.