Effect of TiB2 particles on thermal deformation behavior and mechanical properties of aluminum alloy

Abstract

The mechanical properties of the aluminum matrix composite directly affect its application in aerospace, transportation, and other industries. In this study, the effect of TiB2 particles on the comprehensive properties which includes microstructure, thermal deformation behavior, tensile properties, fracture morphology and hardness of Al-Zn-Mg-Cu alloy was analyzed. Furthermore, the microstructures of these alloys were analyzed using energy-dispersive X-ray spectroscopy, X-ray diffraction, scanning electron microscopy, and a metallography microscope. The stress–strain curves and dynamic softening of the two alloys were studied using the thermal compression test. Furthermore, a thermal processing diagram was constructed for comparing the safety and instability processing zones of the alloys. The Vickers hardness test and the tensile test were performed to compare their hardness, tensile properties, and fracture morphologies. The results demonstrated that TiB2 was contributing to the refinement of the grain size. When the deformation temperature and the stress–strain rate were 300–450 °C and 0.01–10 s−1, the alloy exhibited the same stress-strain variation trend during the thermal compression process before and after adding TiB2 particles. But the deformation resistance of the alloy was improved and processing instability zones were reduced from 300–320 °C/2.5–10 s−1 and 430–450 °C/0.2–0.5 s−1 to 420–450 °C/0.2–1 s−1 because of the addition of TiB2 particles. TiB2 particles could also increase the hardness of the alloy by 71.96% and improve the plastic properties and the fracture stress compared with before adding.