Macro-Micro Scale Observation of Cyclic Hardening-Softening and Precipitates Zone of C460

Abstract

Three sets of age hardened aluminum-lithium alloy C460 specimens were produced by oil quenching, air cooling, and furnace cooling and subjected to cyclical, symmetric tension-compression testing. On examination of microstructures with the aid of scanning electron microscopy, precipitates free zones were identified adjacent to grain boundaries. It was also found that the specimens with the smallest precipitates free zones exhibited the highest fatigue strengths.