Research on the drilling micromechanical properties of TiBW/TC4 composites based on drilling force and temperature analysis

TiB whisker-reinforced TiBW/TC4 composites are widely used in the aviation, aerospace, automobile, and various other industries. However, the drilling force and temperature affect a lot on the drilling micromechanical properties of TiBW/TC4 composites. In order to reveal the microscale thermodynamic properties of the composite and promote the optimization of drilling processing, a representative volume element (RVE) model of the composite was built in the Digimat-FE software tool to determine the micromechanical properties and failure mechanism of TiBW/TC4 composites. Based on drilling experiments, the simulation load and boundary conditions were defined. Then, the effects of drilling force and temperature on the micromechanical properties of the composite and the laws of thermodynamics governing TiBW/TC4 composites were carefully analyzed under three different working conditions: pure drilling force, pure drilling temperature load, and drilling force/temperature load. The results show that with the drilling force rapidly increasing, the maximum stress occurs within the reinforced phase of the composite during the drilling process, whereas the minimum stress appears within the basket matrix region of the reinforced phase. Strains in the matrix were clearly higher than in the whiskers. Stability within the composite material was compromised as the matrix began to fail. The drilling force was shown to be the main reason for failure of the material, whereas the drilling temperature did not appear inherently weaken the material structure, but can, in fact, slow down the impact of the drilling force. When the drilling force began to slowly decrease and tended to stabilize, the stress slowly decreased as well. Although the stress on the whiskers was higher than the matrix stress, the difference value between whiskers and the matrix was constantly shrinking, and the stress of the whole model tended to be uniform.