Zhichao Yang

Bio: Zhichao Yang is an academic researcher from Northeastern University (China). The author has contributed to research in topics: Materials science & Machining. The author has an hindex of 9, co-authored 23 publications receiving 342 citations.

Review of ultrasonic vibration-assisted machining in advanced materials

Abstract: Compared to conventional machining (CM), ultrasonic vibration-assisted machining (UVAM) with high-frequency and small-amplitude has exhibited good cutting performances for advanced materials. In recent years, advances in ultrasonic generator, ultrasonic transducer, and horn structures have led to the rapid progress in the development of UVAM. Following this trend, numerous new design requirements and theoretical concepts have been proposed and studied successively, however, very few studies have been conducted from a comprehensive perspective. To address this gap in the literature and understanding the development trend of UVAM, a critical overview of UVAM is presented in this study, covering different vibration-assisted machining styles, device architectures, and theoretical analysis. This overview covers the evolution of typical hardware systems used to achieve vibratory motions from the one-dimensional UVAM to three-dimensional UVAM, the discussion of cutting characteristics with periodic separation between the tools and workpiece and the analysis of processing properties. Challenges for UVAM include ultrasonic vibration systems with high power, large amplitude, and high efficiency, as well as theoretical research on the dynamics and cutting characteristics of UVAM. Consequently, based on the current limitations and challenges, device improvement and theoretical breakthrough play a significant role in future research on UVAM.

Recent research and development status of laser cladding: A review

Abstract: In industries such as aerospace, petrochemistry and automobile, many parts of different machines are under environment which shows high temperature and high pressure, and have their proneness to wear and corrosion. Therefore, the wear resistibility and stability under high temperature need to be further improved. Nowadays, Laser cladding (LC) is widely used in machine parts repairing and functional coating due to its advantages such as lower dilution rate, small heat-affected zone and good metallurgical bonding between coating and substrate. In this paper, LC is introduced in detail from aspects of process simulation, monitoring and parameter optimization. At the same time, the paper gives a comprehensive review over LC material system as high entropy alloys (HEAs), amorphous alloy and single crystal alloy have been gradually showing their advantages over traditional metal materials in LC. In addition, the applications of LC in functional coatings and in maintenance of machine parts are also outlined. Also, the existing problems and the development trend of LC is discussed then.

Microstructure and mechanical properties of parts formed by ultrasonic vibration-assisted laser cladding of Inconel 718

Abstract: Laser cladding has shown advantages in metal component forming. However, the accompanying issues, such as inner microstructural defects and poor mechanical properties, require further investigation. In this study, laser cladding technology was combined with ultrasound to improve the performance of the formed parts. Based on the cooperative effect of acoustic streaming and acoustic cavitation during the metal solidification process, the influence of the vibration parameter on the degree of undercooling and nucleation rate of the molten metals was investigated. The experimental results show that the grain size obtained under the application of ultrasonic vibration was finer than that obtained under condition of conventional laser cladding. When the amplitude was 25 μm, the average grain size was 0.522 times of that of non-vibration. The phase structure of the precipitates and the chemical composition changed markedly. In addition, the effects of high-frequency vibration on the mechanical properties of the cladding layer were also analysed through contrast experiments. The results indicate that applying high-frequency vibration can effectively reduce porosity, while improving the microhardness and wear resistance. Quantitatively, the friction coefficient was 0.628 times that without ultrasound and 0.709 times that of conventional processing when the amplitude was 25 μm.

Review of ultrasonic vibration-assisted machining in advanced materials

Abstract: Compared to conventional machining (CM), ultrasonic vibration-assisted machining (UVAM) with high-frequency and small-amplitude has exhibited good cutting performances for advanced materials. In recent years, advances in ultrasonic generator, ultrasonic transducer, and horn structures have led to the rapid progress in the development of UVAM. Following this trend, numerous new design requirements and theoretical concepts have been proposed and studied successively, however, very few studies have been conducted from a comprehensive perspective. To address this gap in the literature and understanding the development trend of UVAM, a critical overview of UVAM is presented in this study, covering different vibration-assisted machining styles, device architectures, and theoretical analysis. This overview covers the evolution of typical hardware systems used to achieve vibratory motions from the one-dimensional UVAM to three-dimensional UVAM, the discussion of cutting characteristics with periodic separation between the tools and workpiece and the analysis of processing properties. Challenges for UVAM include ultrasonic vibration systems with high power, large amplitude, and high efficiency, as well as theoretical research on the dynamics and cutting characteristics of UVAM. Consequently, based on the current limitations and challenges, device improvement and theoretical breakthrough play a significant role in future research on UVAM.

Advances in micro milling: From tool fabrication to process outcomes

Abstract: Micro milling cutters or micro mills are unique and important micro tools for fabricating miniaturised devices with sufficient geometrical and dimensional accuracy and machined surface integrity. Micro milling cutters, compared to conventional macro tools, have significantly different material removal mechanisms. They are also made of different raw materials and structures and exhibit distinctive machining characteristics and performances. Herein, we present the first comprehensive and up-to-date review of micro milling cutters in terms of their uniqueness, material removal mechanisms, materials and compositions, structures and design, fabrication techniques and machining performances, to provide adequate guidance for interested involvers. We also outline and discuss several possible future research directions to offer potential insights for the micro milling community and future researchers.

Science and art of ductile grinding of brittle solids

Abstract: Prior to any practical application, brittle material components may need to be machined to a high degree of precision in order to avoid functional breakdown as well as to maintain exacting surface dimensional integrity and retain strength. This usually means grinding in the ductile region. Optimization of the grinding process can shorten manufacturing time and cost and prolong component lifetime. This article reviews the current state of the art of ductile grinding and outlines the underlying science behind pertinent machining events. Engineering aspects of the grinding process will be surveyed, with consideration of wheel requirements and of such variables as grit characteristics, strain rate and temperature. Attention will be given to the fundamental role of removal processes from individual and cumulative microcontacts, using nanoscratch mechanics as the underlying basis for analysis. The critical influence of diversity in material microstructures in determining local deformation mechanisms and subsequent material removal will be highlighted. Practical requirements for optimal ductile grinding will be indicated.