The nonequilibrium solidification of liquid Al72.9Ge27.1 hypoeutectic alloy is accomplished by using single−axis acoustic levitation.A maximum undercooling of 112 K(0.16TL)is obtained for the alloy melt at a cooling r...The nonequilibrium solidification of liquid Al72.9Ge27.1 hypoeutectic alloy is accomplished by using single−axis acoustic levitation.A maximum undercooling of 112 K(0.16TL)is obtained for the alloy melt at a cooling rate of 50 K/s.The primary(Al)phase displays a morphological transition from coarse dendrite under a normal conditions to equiaxed grain under acoustic levitation.In the(Al)+(Ge)eutectic,the(Ge)phase exhibits a conspicuous branched growth morphology.Both the primary(Al)dendrites and(Al)+(Ge)eutectics are well refined and the solute content of the primary(Al)phase is extended under acoustic levitation.The calculated and experimental results indicate that the solute trapping effect becomes more intensive with the enhancement of bulk undercooling.展开更多
基金by the National Natural Science Foundation of China under Grant No 50971105the Fundamental Research Foundation of Northwestern Polytechnical University under Grant Nos JC201050 and G9KY1021.
文摘The nonequilibrium solidification of liquid Al72.9Ge27.1 hypoeutectic alloy is accomplished by using single−axis acoustic levitation.A maximum undercooling of 112 K(0.16TL)is obtained for the alloy melt at a cooling rate of 50 K/s.The primary(Al)phase displays a morphological transition from coarse dendrite under a normal conditions to equiaxed grain under acoustic levitation.In the(Al)+(Ge)eutectic,the(Ge)phase exhibits a conspicuous branched growth morphology.Both the primary(Al)dendrites and(Al)+(Ge)eutectics are well refined and the solute content of the primary(Al)phase is extended under acoustic levitation.The calculated and experimental results indicate that the solute trapping effect becomes more intensive with the enhancement of bulk undercooling.
