In situ measurements of local strain in heterogeneous materials

The local strain during tensile tests in an AlSi7 alloy, a 6061 alloy reinforced with 10vol.% of Al2O3 particles, and a 20vol.% Al2O3 short fibre reinforced AlSi12CuMgNi alloy have been examined. Superficial strain fields were calculated from secondary electron images at different stages of deformation during tensile tests using an in-situ tester inside electron microscope (SEM). During tensile tests in AlSi7, deformation bands at 45-50° with respect to the tensile direction were formed. High concentration of strain was mostly observed in the α-phase, while much lower values were recorded in the Al-Si eutectic region. In the short fiber reinforced composites, high concentration of strain were observed at corners of fibers aligned in the tensile direction or with perpendicular orientation. High degree of local deformation in regions with low particle density was observed in the 6061/Al2O3/10p composite.