Dynamic compression properties and failure mechanisms of (TiC + (TiZr)₅Si₃)/TA15 composites

The research fabricated a titanium matrix composite with multi-scale reinforcements and examined its compressive behavior and microstructural evolution across different strain rates. The composite showed limited strain rate sensitivity at low rates, with yield strength increasing only marginally from 1288 MPa (0.001 s⁻¹) to 1312 MPa (0.1 s⁻¹). In contrast, high strain rates induced significant strain rate hardening: yield strengths reached 1641 MPa, 1728 MPa, and 1816 MPa at 1243 s⁻¹, 2207 s⁻¹, and 3342 s⁻¹, representing increases of 27.4% ∼ 41.0% over the quasi-static value. Deformation mechanism analysis indicated a transition from dislocation slip (activation volume ∼ 48 b³) at low rates to nucleation-dominated mechanisms (∼1.5 b³) at high rates, explaining the observed hardening. Under dynamic shear, localized thermal softening from plastic work overcame strain hardening, triggering adiabatic shear bands. TiC/matrix interfaces failed due to thermal mismatch and shear, forming microvoids that initiated cracks. In contrast, (TiZr)₅Si₃/matrix interfaces retained excellent integrity, delaying damage progression.