Effects of ultrasonic irradiation and cooling rate on the solidification microstructure of Sn–3.0Ag–0.5Cu alloy
Effects of ultrasonic irradiation and cooling rate on the solidification microstructure of Sn–3.0Ag–0.5Cu alloy
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DOI：
10.1016/j.jmatprotec.2013.07.013
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发表时间：
2014
影响因子：
6.3
通讯作者：
H. Ji;Qiang Wang;Mingyu Li;Chunqing Wang
中科院分区：
文献类型：
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作者：
H. Ji;Qiang Wang;Mingyu Li;Chunqing Wang
对超声辅助凝固生长的Sn-Ag-Cu合金铸锭的显微组织进行了对比研究，重点研究了熔体凝固过程中冷却速度对超声处理深度和时间的限制。空冷过程中，超声功率的增加降低了合金的过冷温度，延长了合金的凝固时间，使β-Sn相由枝晶状破碎为等轴晶状。晶粒尺寸从约300 μm减小到20 μm。当冷却速率从空气中的4 °C/s增加到水中的20 °C/s时，宏观过冷温度通过超声功率的增加而大大降低，但凝固时间似乎仅略有变化，因为在熔体中仅允许有限的超声处理时间。在两种冷却速率下，组织沿加工深度沿着是不均匀的。超声空化和声蒸汽作用的深度和周期是导致凝固组织差异的主要原因。
A comparative study on the microstructures of Sn–Ag–Cu alloy ingots grown by ultrasound-assisted solidification was carried out with a specific focus on the limits on the ultrasonic processing depth and time imposed by the cooling rate during the melt solidification. During air-cooling, increasing the ultrasonic power reduced the undercooling temperature and increased the solidification time, leading toβ-Sn phase fragmentation from a dendritic shape into a circular equiaxed shape. The grain size was decreased from approximately 300 μm to 20 μm. When the cooling rate was increased from 4 °C/s in air to 20 °C/s in water, the macro-undercooling temperature was more greatly reduced by an increase in ultrasonic power, but the solidification time seemed to change only slightly because only a limited period for ultrasonic processing was permitted in the melt. Under both cooling rates, the microstructures were inhomogeneous along the processing depth. The functional depth and period for ultrasonic cavitation and acoustic steaming contributed to the differences in the solidification microstructures.