Side grooving of specimens can have a pronounced effect on the fracture behavior of aluminum alloys during plane-strain fracture tests. The first part of this paper describes an investigation of the effect of different amounts of side grooving on KIc determined using compact specimens of varying thicknesses machined from a 6061-T651 plate. The results are also related to KIv measurements made on the same material and are discussed in terms of rising R-curve effects on compact and short-bar fracture specimens.
Chevron-notch fracture tests in accordance with ASTM E 1304-89 were also carried out on nominally 13-mm-thick plates of aluminum alloys 2024-T351, 7075-T651, and 8090-T8771. Various specimen orientations were used, including both in-plane and short-transverse loading. Tension and also, where possible, compact specimen fracture tests have also been carried out on the same plates.
Data are presented showing the variation in load-deflection behavior and measured toughness with alloy type, and also with specimen orientation. Correlations of toughness and strength with plate rolling direction have been made. Problems arising from the E 1304 test method are also highlighted.