The effect of ultrasonic treatment on the formation of primary Al3Zr was investigated by applying ultrasound to an Al?0.4Zr alloy.Three temperature ranges were selected,i.e.,830to790°C(above liquidus),790to750...The effect of ultrasonic treatment on the formation of primary Al3Zr was investigated by applying ultrasound to an Al?0.4Zr alloy.Three temperature ranges were selected,i.e.,830to790°C(above liquidus),790to750°C(cross liquidus)and750to710°C(below liquidus)for ultrasonication.Using the scanning electron microscopy,both the size and morphology of the primary Al3Zr particles were examined.It was found that the size was significantly reduced and the morphology changed from large throwing-star shape to small compact tablet shape.The mechanisms for refinement of primary Al3Zr were discussed.It is suggested that sonocrystallization theory via activation of aluminium oxide particles is responsible for the refinement of primary Al3Zr when ultrasonic melt treatment(UST)is applied within the fully liquid state.The refinement of primary Al3Zr particles when UST is applied in the slurry(growth stage)is due to the sonofragmentation.展开更多
基金support from UK Engineering and Physical Science Research Council (EPSRC) for the Ultra-Cast project (grant EP/L019884/1, EP/L019825/1, EP/L019965/1)
文摘The effect of ultrasonic treatment on the formation of primary Al3Zr was investigated by applying ultrasound to an Al?0.4Zr alloy.Three temperature ranges were selected,i.e.,830to790°C(above liquidus),790to750°C(cross liquidus)and750to710°C(below liquidus)for ultrasonication.Using the scanning electron microscopy,both the size and morphology of the primary Al3Zr particles were examined.It was found that the size was significantly reduced and the morphology changed from large throwing-star shape to small compact tablet shape.The mechanisms for refinement of primary Al3Zr were discussed.It is suggested that sonocrystallization theory via activation of aluminium oxide particles is responsible for the refinement of primary Al3Zr when ultrasonic melt treatment(UST)is applied within the fully liquid state.The refinement of primary Al3Zr particles when UST is applied in the slurry(growth stage)is due to the sonofragmentation.
