Effect of mixed mode I/III loading on fracture toughness of 7010 aluminium alloy

Abstract

The effect of mixed mode I/III loading on the fracture toughness of 7010 aluminium alloy plate was investigated in the peak aged (T6) and overaged (T73) temper conditions. The fracture toughness of 7010 Al alloy was found to remain more or less unchanged with increasing mixed mode I/III loading for both aging tempers. The fracture, in both T6 and T73 tempers, occurred predominantly by a transgranular ductile mechanism of void nucleation, growth and coalescence under mode I as well as mixed mode I/III loading. Primary void formation at brittle intermetallic inclusions and their subsequent coalescence was determined to be the most important step in the fracture process. This coupled with the nature of the stress field ahead of the crack tip under mixed mode I/III loading was then used to explain the insignificant effect of mixed I/III loading on the fracture toughness in 7010 aluminium alloy.

Keywords

7010 ALUMINIUM ALLOY MIXED MODE I/III FRACTURE TOUGHNESS AGING

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