Yield loci of FCC and BCC sheet metals

Yield loci of deep drawing steel, ferritic and austenitic stainless steels, 70/30 brass, annealed copper and aluminum sheet metals were analyzed. Experimental results were compared to predictions obtained by different proposed yield loci equations. Yield loci of BCC materials were described by Hill's new equation with exponents between 1.90 and 2.0. Yield loci of FCC alloys, showing in-plane isotropy (70/30 brass and austenitic stainless steel), were described by Hosford's equation with high values (8 or 10) for the a exponent. The yield locus of annealed copper, showing significant in-plane anisotropy, can be approximately described by Barlat's equation with a high m exponent (m=8). The yield locus of annealed aluminum was close to Tresca's criterion, not considering the anisotropy of mechanical properties at 45 degrees. (C) 1997 Elsevier Science Ltd.