YIELD FUNCTION DEVELOPMENT FOR ALUMINUM-ALLOY SHEETS

In this work, yield surfaces were measured for binary aluminum-magnesi um sheet samples which were fabricated by different processing paths t o obtain different microstructures. The yielding behavior was measured using biaxial compression tests on cubic specimens made from laminate d sheet samples. The yield surfaces were also predicted from a polycry stal model using crystallographic texture data as input and from a phe nomenological yield function usually suitable for polycrystalline mate rials. The experimental yield surfaces were found to be in good agreem ent with the polycrystal predictions for all materials and with the ph enomenological predictions for most materials. However, for samples pr ocessed with high cold rolling reduction prior to solution heat treatm ent, a significant difference was observed between the phenomenologica l and the experimental yield surfaces in the pure shear region. In thi s paper, a generalized phenomenological yield description is proposed to account for the behavior of the solute strengthened aluminum alloy sheets studied in this work. It is subsequently shown that this yield function is suitable for the description of the plastic behavior of an y aluminum alloy sheet. (C) 1997 Elsevier Science Ltd.