Cyclic deformation behavior of in situ aluminum–matrix composites of the system Al–Al3Ti–TiB2–Al2O3

Aluminum-based composites reinforced with in situ ceramic TiB2 and Al2O3 particulates as well as intermetallic Al3Ti phase were prepared through reactive hot pressing of powders from the Al–TiO2–B2O3 and Al–TiO2–B systems. In situ composite derived from the Al–TiO2–B2O3 system exhibited lower yield and tensile strengths but higher tensile ductility due to its lower Al3Ti content. The low cycle fatigue behavior of in situ composites prepared from such systems under total strain-controlled conditions at room temperature was investigated. At low strain amplitudes, stable cyclic response was observed in the in situ composites fabricated from the Al–TiO2–B2O3 and Al–TiO2–B systems. However, initial cyclic hardening followed by softening occurred in the composite prepared from Al–TiO2–B2O3 system. The fatigue damage was observed to initiate in brittle Al3Ti blocks. Thus composite fabricated from Al–TiO2–B2O3 system had longer fatigue lives. The fatigue life data of in situ composites can be described by the Coffin–Manson relationship.