Atomic simulation of the effect of UEVC depth on subsurface damage of single crystalγ-TiAl alloy

RC Feng and YC Chen and H Cao and HY Li and CY Han and WK Chen and T Chen, MACHINING SCIENCE AND TECHNOLOGY, 29, 906-929 (2025).

DOI: 10.1080/10910344.2025.2531989

TiAl alloys, brittle at room temperature with low thermal conductivity, face high cutting forces and temperatures during machining, impacting subsurface quality. However, ultrasonic elliptical vibration cutting (UEVC) can significantly mitigate subsurface damage in these hard-to- machine materials. In this article, an MD model is established to analyze the temperature variations, elastoplastic deformation and dislocation evolution within a vibration cycle of UEVC single-crystal gamma-TiAl alloy and to investigate the influence of UEVC depth on cutting force, temperature, atomic plastic flow and subsurface damage depth. It is demonstrated that the average cutting force increases with cut depth, and the atomic orientation varies as a function of the cutting force. When the cutting force reaches the threshold for dislocation activation, dislocation slip occurs, leading to an increase in the depth of the subsurface damage layer. Throughout the UEVC process, from initial tool-workpiece contact to their separation, the maximum temperature exhibits a decreasing trend. Moreover, dislocation slips and annihilation at the tool's front form an elastic recovery zone, mitigating subsurface damage. Atomic orientation changes a lot in both shear slip and elastic recovery zones, with less dislocation activity. Simulations provide a theoretical basis for minimizing subsurface damage in TiAl alloy processing.

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