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 de position was studied. This alloy has a composite type structure compos ed of silicon and intermetallic particles in an aluminium matrix. In s itu tensile tests in the SEM, with gold microgrids deposited on the su rface of the specimen as an indicator of local plastic strains, provid e us with a better understanding of the damage process from crack init iation to fracture. In the T4 temper, the first cracks appear in silic on particles; they initiate shearings and/or decohesions in the matrix , which develop along grain boundaries. Just before the brittle failur e of the sample, the generalized microcracking involves both silicon-p article cracking and grain-boundary decohesions.