中文摘要：

主要介绍功率超声在金属熔体成形领域中的作用，详述了超声在铸造成形、辅助焊接成形中细化晶粒、除气除杂、强化焊缝、减小残余应力、促进界面润湿等方面的应用和作用机理。针对超声空化气泡的高速摄影及金属熔体中晶体生长的同步辐射X射线成像观察的研究进展，提出将高速摄影与同步辐射X射线成像结合起来，通过原位观察方法研究超声波与液态金属媒质的相互作用机理，为进一步促进超声在金属熔体成形中的应用提供理论指导。

英文摘要：

The effect of power ultrasound in molten metal shaping was summarized. The application and mechanism of ultrasonic treatment in the grain refinement, degassing and impurity removal in casting process, as well as strengthening of weld seam by reducing residual stress and promoting interfacial wetting in welding process were reviewed in details. The progress in high-speed photography of ultrasonic cavitation bubbles and synchrotron radiation X-ray imaging of crystal growth in molten metal was reviewed and discussed. It was proposed to adopt in-situ investigation of mechanism of ultrasound in liquid metal medium by combining high-speed photography and synchrotron radiation X-ray imaging. It aims to provide theoretical guidance for further applications of ultrasound in the molten metal shaping.