Investigation on the high-temperature ductility and fracture mechanisms of an in-situ particle reinforced Al matrix composite 7075Al/TiB2

Abstract

In order to investigate the high-temperature ductility and fracture mechanisms of in-situ TiB2 particle reinforced 7075 Al matrix composites, the tensile behaviors and fracture mechanisms of the composite were investigated in the temperature range 350–450 °C and strain rate range of 0.001s−1–0.1 s−1. The effects of temperature, strain rate, and the TiB2 particles on the deformability and fracture of the composite were evaluated. The investigation revealed that the influence of temperature on the ductility of the composite is remarkable but non-monotonic, while the strain rate exhibits less effect. Temperature significantly increases the ductility of the composite when it below 400 °C while decreases the ductility when it above 400 °C. Fractographic morphologies manifested that matrix rupture in the form of void nucleation and growth is the main fracture mechanism of the composite at high temperature. Additionally, interface debonding increasingly affects the damage and fracture of the composite at elevated temperatures or lower strain rates. An optimal hot working condition for the in-situ 7075Al/TiB2 composite was suggested.