A STUDY OF DAMAGE UNDER TENSILE LOADING IN A NEW AL-SI-FE ALLOY PROCESSED BY THE OSPREY ROUTE

The mode of damage in tension of a new Al-Si-Fe alloy made by spray deposition was studied. This alloy has a composite type structure composed of silicon and intermetallic particles in an aluminium matrix. In situ tensile tests in the SEM, with gold microgrids deposited on the surface of the specimen as an indicator of local plastic strains, provide us with a better understanding of the damage process from crack initiation to fracture. In the T4 temper, the first cracks appear in silicon particles; they initiate shearings and/or decohesions in the matrix, which develop along grain boundaries. Just before the brittle failure of the sample, the generalized microcracking involves both silicon-particle cracking and grain-boundary decohesions.