Evaluating Potential Fatigue Performance of Composites (Cu/W and Cu/Mo) from Microstructural Behavior
SourceHelical coils of tungsten or molybdenum were embedded in a copper matrix to test whether potential fatigue performance of composites might be simply evaluated from microstructural behavior. When these composites were tested in alternating torsion, the wire coils caused the matrix to develop “hard” layers where deformation was small and “soft” ones where it was intense. The intensity and type of deformation in a soft layer could correspond to that produced by large strain amplitudes even when the nominal amplitude applied to a specimen was small. Thus, fatigue performance of these composites was, in general, no better than that of the matrix alone. But it was considerably improved in special arrangements where the wires were designed to act as crack stoppers and the mode of fatigue straining was appropriately adapted.