A study of the effects of particle 3-dimensional geometry and micro-texture on fatigue crack initiation behaviors in an Al–Cu alloy using focused ion beam and electron backscatter diffraction

Multiple cracks were generated from surface particles in an Al–Cu alloy in four-point bend fatigue. These cracks mostly became non-propagating at or shortly beyond the particle/matrix interface on the surface. Cross-sectioning using focused ion beam revealed that the 3-dimensional geometry, especially the thickness, of fractured particles was the key factor controlling the driving force for micro-crack growth. The resistance to micro-crack growth was mainly associated with crack plane twist at the particle/matrix interface, as revealed by electron backscatter diffraction measurement.