Effects of TiB2 particles on aging behavior of in-situ TiB2/Al-Cu-Mg composites

In this study, the evolution of microstructures and properties of in-situ 5 wt% TiB2/Al-Cu-Mg composites during artificial aging has been systematically investigated. Various techniques including scanning electron microscopy (SEM), transmission electron microscopy (TEM), Vicker׳s hardness (HV), differential scanning calorimetry (DSC), and electrical resistivity measurement have been used to study the effect of second phase TiB2 particles on the aging process. At an aging temperature of 180 °C, the hardness of the composites shows two peak behaviors as functions of aging time. DSC and resistivity measurements suggested that the precipitation in the composites has a two-step process. The aging process of the composites has been discussed in terms of precipitation mechanisms combined with the effect of the particles.