Fatigue of polycrystalline copper with different grain sizes and texture

Fatigue experiments of polycrystalline copper with different grain sizes and texture were conducted under tension–compression, torsion, and non-proportional loading. The grain sizes ranged from 10 μm to 2 mm. The stress–strain response was found to be a strong function of the grain size and texture. A plasticity-based critical plane multiaxial fatigue criterion was used to predict the fatigue lives of the polycrystalline copper. It was found that the criterion was able to correlate all the experimental results with one single set of material constants. This indicates that the fatigue failure of the material under consideration is dominated by the fatigue resistance of the grains with an insignificant influence of the grain boundaries on the fatigue of the polycrystalline material. It was found that the fatigue model with the material constants obtained from fatigue experiments can be applied to predict failure under monotonic torsion.