A new characterisation method for stress, hardness, microstructure, and slip lines using the stored energy field in the cutting deformation zones of workpiece. (July 2022)

• Record Type: Journal Article
• Authors: Tang, Zhengyi; Huang, Chuanzhen; Shi, Zhenyu; Li, Binghao; Liu, Hanlian; Niu, Jiahui; Chen, Zhen; Jiang, Guoyan
• Is Part Of: International journal of machine tools & manufacture. Volume 178(2022)
• Publication Date: 2022-07
• Subjects: Cutting process behaviour -- Deformation mechanism -- Stored energy -- Microstructure -- Mechanical properties; Machine-tools -- Periodicals; Manufacturing processes -- Periodicals; Machines-outils -- Périodiques; Fabrication -- Périodiques; Electronic journals; 621.902
• DOI: 10.1016/j.ijmachtools.2022.103891
• Languages: English
• ISSNs: 0890-6955

Abstract

Abstract: This study attempts to comprehensively characterise the cutting process behaviour based on the stored energy field in the cutting deformation zones. Studying the cutting mechanism is difficult because the cutting process is accompanied by complex macro- and micro-phenomena. Therefore, it is proposed that the stored energy inside the deformed materials can be selected as the characterisation index of the cutting process behaviour including the stress, hardness, microstructure, and slip lines in the cutting deformation zones. The stored energy prediction model and constitutive model are established based on the hardening behaviour and microstructure evolution mechanism of the material. These models are then integrated into a finite element cutting model to obtain the stored energy field in the orthogonal cutting process. The simulation results are verified by combining transmission electron microscopy analysis and image quality method using electron backscatter diffraction technology. The relationships between the stored energy field and the distributions of the microstructure, stress and hardness are discussed. The results demonstrate that the subgrain size can be accurately predicted based on the stored energy. The distribution laws of the stress and hardness in the cutting deformation zones can be reflected by the stored energy field, and a convenient method for predicting the stored energy field by the hardness distribution is proposed and verified. Based on the aforementioned results, the formation mechanisms of the chips and the machined surface are analysed, and it is found that the slip lines can be sufficiently characterised by the gradients of the stored energy field. The cutting forces, chip thickness, and shear angle can be accurately predicted at different cutting speeds, indicating the reliability of the constitutive model. Moreover, the deformation characteristics of hardened zone are analysed and the thickness is estimated based on the stored energy field. Graphical abstract: Image 1 Highlights: Obtain stored energy evolution model by hardening behaviour and micro mechanisms. Characterise cutting process behavior by stored energy field in cutting deformation zones. Propose an experimental method to obtain stored energy field combining TEM and EBSD analysis. Predict the stored energy field by hardness distribution of the chip roots. Analyse the formation mechanisms of chips and machined surface based on stored energy field.