基于声悬浮的非透明材料内部微结构超声聚焦加工方法研究

随着飞秒激光聚焦透明材料内部点蚀加工成形技术兴起，材料内部微结构封闭式加工方法（简称“内加工”）应运而生。而非透明材料例如黑色系金属合金内部微结构内加工方法尚未提出。项目提出黑色系金属合金中内部微结构内加工方法新方案。首先，应用超声悬浮技术，将处于固-液临界相变状态金属合金坯料悬浮于超声驻波节点位置；然后，应用相控超声阵列动态聚焦技术将超声阵列依次聚焦于悬浮坯料内部并点蚀加工成形。方案中，超声聚焦作用关键，引入激光超声技术、声孤立子理论研究建立超声非线性聚焦理论和方法。首先，研究高温表面激光激发声孤立子条件；然后，研究声孤立子在坯料内部时变温变结构中传播规；研究超声驻波势阱焦域中对声孤立子吸引、纠缠与相干机制；研究非线性作用聚变聚焦点蚀加工机理；最后，通过试验研究和数值分析手段，验证非透明黑色系金属合金坯料内部微结构超声聚焦加工理论和方法，并努力探索不同基体材料-构件封闭空间内加工成形方法

With the rising of inner processing technology of micro internal structure in transparent materials (such as polymer dielectric material PMMA) by femtosecond laser and the application of high intensity focused ultrasound (HIFU) to eroding organisms target material, a new technology of directly manufacturing internal structure in the material, referred to as "inner processing" technology, has been rapidly developing. But the directly processing technology of inner micro structure in non transparent material such as metal has not yet been put forward. A new technology scheme of the metal inner processing technology using ultrasonic suspension, acoustic array focusing etc was proposed in this project. The solid-liquid metal material under temperature control is suspended in the standing wave node by ultrasonic levitation technique, and the phased array is dynamically focused on the inside of the blank, there are pitting to form a structure. Focusing performance and temperature control in this technology play an important role in this advanced technical system. Aiming at solving the lower focusing performance technical problem of the existing phased array ultrasonic array, the theory of acoustic soliton was introduced in this project. Study on the propagation law of acoustic solitons in time varying and temperature varying structure, on the mechanism of attraction and agglomeration effect of acoustic solitons by ultrasonic standing wave trap will being conducted. The nonlinear coherent interaction condition and formation law of acoustic soliton in potential well will be revealed. Results will lead to the greater improving of the machining ability and positioning accuracy of the focused point. The theory and method of ultrasonic focusing in the microstructure of metallic and other non transparent materials then be roughly explored. Fabrication of three dimensional hollow microstructures in non transparent materials of metal alloy will be realized. The existing inner processing technology system will be further enriched.