Research on the optimization design of gradient ceramic cutting tools based on thermomechanical coupling mechanism

Gradient ceramic tools (GCT) have a wide range of potential applications due to their excellent thermodynamic properties and cost-effectiveness. Material distribution is a key factor affecting the performance of GCT. Currently, the material distribution status lacks adaptability with existing forming methods, which limits the further application of GCT. Additive manufacturing allows for the free forming of GCT, but there are issues of time-consuming and inaccurate data in optimizing the thermodynamic performance of GCT through experimental measurements. Therefore, in the context of additive manufacturing, a center-symmetric gradient (CSG) ceramic tool was designed using thermodynamic coupling simulation, and its thermodynamic coupling mechanism was subsequently examined. Firstly, the heat conduction theory is utilized to establish the heat conduction model of CSG ceramic tool. Subsequently, the thermal stress field is analyzed and simulated. The results indicate that the thermal stress accumulates during the initial stage I of CSG as the thermal shock time progresses. In the subsequent stage II of thermal shock duration, the maximum thermal stress point is located far from the tool tip, and all eight cutting edges are equally effective. Moving on to stage III, which is characterized by zero thermal load, the tool surface temperature decreases rapidly. However, even when the temperature field gradient difference approaches zero, residual thermal stress still persists. This residual stress is identified as the root cause of the tool material performance failure. Based on the thermodynamic coupling mechanism of CSG and additive manufacturing ideas, the three layers CSG and five layers CSG are designed using the finite element method. In sum, this study establishes a theoretical foundation for the design of GCT and serves as a reference for the development of functional devices or multimaterial structures.