Cyclic deformation and dynamically induced short-range ordering in small particles reinforced Al composite

Cyclic deformation of an Al-Cu-Mg composite strengthened by small non-shareable particles was firstly investigated through strain controlled low-cycle fatigue (LCF) tests. In comparison with the reported Al-Cu-Mg composites, the in-situ TiB2/Al-Cu-Mg composite presented higher fatigue life at all the tested strain amplitudes. The composite exhibited cyclic hardening response, which was contributed by non-shareable particles, dislocations and dynamically deformation-induced short-range orderings in the Al matrix. Considering plastic strain evolution, the cyclic hardening model was established and well fitted with experimental results. When cyclic loading was controlled at higher strain amplitudes, the serrated flow occurred on stress-strain hysteresis loops and then it disappeared after the first few cycles related to the occurrence of dynamic strain aging. Onset of the stress serration on stress-strain hysteresis loop was greatly dependent on the strain amplitude rather than cumulative plastic strain. Finally, the correlative cyclic hardening model of small particles reinforced Al composite was analytically discussed based on microstructure evolution and cyclic stress-strain responses.

Automated summary

Cyclic deformation of an Al-Cu-Mg composite strengthened by small non-shareable particles was investigated using strain controlled low-cycle fatigue tests. The in-situ TiB2/Al-Cu-Mg composite showed higher fatigue life compared to reported composites. The cyclic hardening response was attributed to non-shareable particles, dislocations, and dynamically deformation-induced short-range orderings. The cyclic hardening model, considering plastic strain evolution, was well fitted with experimental results. The onset of stress serration was found to be dependent on strain amplitude rather than cumulative plastic strain.