An enhanced shear-lag model considering temperature-dependent whisker fracture and de-bonding mechanism for TiB whisker-reinforced titanium matrix composites

Accurately evaluating whisker contributions to high-temperature strength is crucial for advancing TiB whisker-reinforced titanium matrix composites (TMCs). A key challenge lies in quantitatively characterizing temperature-dependent whisker fracture and interfacial de-bonding. This study enhances the shear-lag model by incorporating micromechanical analysis of distinct failure modes and systematically investigates the tensile failure behaviors of TiBw/TC4 TMCs over the temperature range of 25–700 °C. Experimental results reveal a transition from whisker fracture below 260 °C to de bonding above 450 °C, with mixed failure modes observed between 260 °C and 450 °C. Complete failure occurs at 650 °C. The enhanced model effectively captures these transitions with varied temperatures. In fracture and mixed failure regions below 500 °C, whisker strengthening factors of 11 14 and strengthening efficiencies of 30–70 MPa/vol.% were quantified, highlighting the significant role of whiskers in reinforcement. Moreover, increasing the whisker aspect ratio in de-bonding regions preserves strengthening efficiency and identifies critical fracture aspect ratios as the optimal whisker size for performance enhancement. The model's accuracy and predictive capability are validated against tensile experiments and literature data. This study provides a simple effective method for strength prediction, offering valuable guidance for high-temperature property design and advanced composite development.