The effect of Fe-rich intermetallics on crack initiation in cast aluminium : an in-situ tensile study

• To evaluate the role of Fe-rich intermetallics on crack initiation, two fully modified Al-Si alloys, one containing plate-like β-Fe and the second containing primary α-Fe intermetallics, were investigated by in-situ tensile testing in the scanning electron microscope. In the first alloy, large plate-like β-Fe intermetallics oriented parallel to the test direction were the first to crack at an elongation of about 1.8%. More transversely oriented intermetallics caused crack initiation in the matrix which linked up with the final fracture. In the second alloy, the cracking of α-Fe intermetallics initiated at an elongation of about 0.9%. It is concluded that large α-Fe intermetallics crack first and that clusters of α-Fe are the most potent crack initiation sites.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

Nyckelord

Al-Si alloy

Cast aluminium

Fracture mechanics

Tensile testing in SEM

α-Fe

β-Fe

Aluminum alloys

Crack initiation

Cracks

Fracture testing

Intermetallics

Materials testing apparatus

Metal testing

Scanning electron microscopy

Silicon alloys

Tensile testing

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