Machining of thin-walled components of fiber-reinforced titanium matrix composites—Dynamic response mechanism of fiber orientation

Thin-walled structural components are widely used in aerospace industries due to their lightweight and high-strength properties. However, their low-rigidity structural characteristics cause machining deformation during processing. For thin-walled components made of continuous silicon carbide fiber-reinforced titanium matrix composites (SiC f /Ti), the simultaneous existence of both metal and fibers, lead to more complex machining deformation than traditional titanium materials or other composites and their deformation mechanism remains unclear. This paper investigates side-milling of SiC f /Ti thin-walled components and revealed that, compared to titanium alloy, their machining process shows global dynamic instability. Specifically, SiC f /Ti components with vertically and horizontally aligned fibers exhibited displacement reductions of 33.2% and 56.93%, respectively, compared to Ti baseline. The machined surface demonstrates the material-response dominance. For vertically aligned fibers, the cutting inlet of SiC f /Ti exhibits lowest stiffness and dominates dynamic instability, with a peak vibration amplitude of 154.3 m/s 2 . In contrast, horizontally aligned fibers show more severe stiffness collapse at the cutting outlet, reaching 160.7 m/s 2 . With vertically aligned fibers, the deformation mechanism of SiC f /Ti is dominated by constrained plastic flow of matrix and elastic coordination at interface. Energy is dissipated efficiently through the friction at fiber-matrix interface and propagation of stress wave along fiber direction, which shows a stable dynamic response. In contrast, horizontally aligned fibers induce the cross-scale laminate bending and interlaminar shear deformation. Energy repeatedly superimposes and accumulates within the fibers with difficulty in dissipation, which keep the system in intense vibrational state. This study provides valuable insights for high quality machining of SiC f /Ti thin-walled components.