Ultrasonic vibration assisted manufacturing of high-performance materials

High-performance materials are broadly applied in many key industries to meet the high requirements of material strength, light weight, corrosion resistance, high-temperature capability, functionality, etc. Manufacturing of high-performance materials is necessary to produce the end-use parts or components that can be effectively applied in industries. However, traditional manufacturing methods could generate various manufacturing problems, which would limit the broad applications of end-use parts. As a type of high-performance materials, carbon fiber reinforced plastic (CFRP) composites have found remarkably increasing applications in the aerospace and automotive industries due to their superior properties. In order to manufacture the CFRP composites to final end-use parts, machining processes including hole making and surface grinding are always planned after the molding processes to generate features on the final parts. However, CFRP composites exhibit a poor machinability in the traditional machining processes, leading to low part quality and low manufacturing efficiency. As another type of high-performance materials, metal alloys such as nickel and titanium possess outstanding properties even at extremely high temperatures. For this reason, they have been extensively used to manufacture engine components in aerospace, defense, and marine industries. Recently, additive manufacturing of these alloys has gained numerous attention with the advantages of wasted material reduction and manufacturing efficiency improvement. However, fabrication defects and uncertain microstructures are inevitably induced in the additively manufactured metallic parts, which are greatly detrimental to the part qualities and mechanical properties. Based on the problems during the manufacturing of those two types of high-performance materials as mentioned above, it is thereby of great significance to develop a high-quality and high-efficiency manufacturing technique to effectively reduce the issues. In recent years, ultrasonic vibration has attracted great interests in assisting numerous manufacturing processes with significant improvements in the manufacturing process performances. Compared with other mechanical vibrations, ultrasonic vibration possesses a frequency that is much higher than the natural frequency of a system. Due to this reason, ultrasonic vibration can maintain or even improve the stability of the manufacturing system without adding harmful low-frequency vibrations. In this dissertation, ultrasonic vibration-assisted (UV-A) manufacturing processes will be thus conducted to seek the potential solutions for the aforementioned manufacturing problems. In this dissertation, a comprehensive literature review on UV-A manufacturing processes is firstly conducted to provide fundamental knowledge on the mechanism of ultrasonic vibration’s actions in all the manufacturing processes. Then, endeavors have been made to facilitate the effective fabrication of the high-performance materials by introducing ultrasonic vibration as an assisted technique in the manufacturing processes. In particular, UV-A machining (hole making and surface grinding) of CFRP composites as well as UV-A laser engineered net shaping of stainless steel, nickel alloys, and titanium matrix composites are experimentally and theoretically investigated. The results show improvements in both process performance and manufactured part quality, which can be attributed to the remarkable influences of ultrasonic vibration. The investigations in this dissertation will help to establish a high-quality and high-efficiency process to improve the CFRP machinability and performance of additively manufactured metal and metal matrix composite parts. In addition, the fundamental understanding and knowledge generated in this dissertation will benefit the area of UV-A manufacturing of high-performance materials.