Multiscale analysis on the effect of laser preheating on the fabrication of micro-textured surface of titanium alloy by laser-ultrasonic-vibration assisted cutting

Résumé fourni par la source

Abstract Surface texturing has emerged as an effective approach for enhancing the surface performance of mechanical components. To achieve the efficient, high-quality, and controllable fabrication of the micro-textured surface of Ti6Al4V, a surface texturing method of laser-ultrasonic-vibration assisted cutting (LUVC) is proposed. The application of ultrasonic vibration in the direction of depth of cut (DOC) can change the cutting trajectory to generate the even-distributed micro-dimples on the workpiece surface. The purpose of the combination of laser preheating is to reduce the machining difficulty of Ti6Al4V and improve the fabrication quality of micro-dimples. In order to systematically research the effect of laser preheating on the fabrication of micro-textured surface of Ti6Al4V, the multiscale analysis is conducted based on a finite element method (FEM) model of LUVC, which is established in the DEFORM-2D software by incorporating the grain evolution and the laser preheating. The results show that the laser preheating can not only improve the processing performance of surface texturing of Ti6Al4V, including reducing the cutting force and the tool wear, but also enhance the grain refinement in the subsurface layer of the micro-textured surface. The increase of laser power is more conducive to reducing the cutting force and the wear on both rake face and flank face of tool. The higher the laser power, the greater the degree of grain refinement and the deeper the refinement layer. Besides, the laser preheating can also enhance the material’s plasticity and flowability, which in turn affects the size and profile of the dimple. As the laser power increases, the corresponding dimple depth also increases. The numerical analysis in this study can not only offer a constructive guidance for future experimental exploration, but also provide a research foundation for further optimizing the processing parameters of LUVC to fabricate a much better micro-textured surface of Ti6Al4V.

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