The tensile, notch tensile, tear, and, in some cases, fracture-toughness properties (K_Q and K_Ic, ksi √in.) have been evaluated for 3-in.-thick 5083-H321, 5086-H32, 6061-T651, and 7005-T6351 plain plate and gas metal arc (GMA) welds in 5083-H321 (5183 filler), 6061-T651 (4043 and 5356 fillers), and 7005-T6351 (5356 filler) with no subsequent thermal treatment. The tests were made in the longitudinal, long-transverse and short-transverse orientations for the plain plate and in the “cross-weld” orientation for the welded panels. The tests were made at room temperature and generally at −100 and −320°F.

The fracture indexes, that is, notch-yield ratio and unit-propagation energy values, rank the plate and welds. The K_Q and K_Ic values have been developed for the 6061-T651 and 7005-T6351 plate.

For the relatively tough materials in this investigation, the notch-yield ratio versus K_Ic relationship was not useful in estimating K_Ic values. However, the unit-propagation energy values versus K_Ic relationship does appear to provide a satisfactory means of estimating K_Ic values. Estimates of K_Ic values for all the materials tested in this program have been made from this correlation.