Abstract: Biaxial tensile tests of directionally solidified superalloy IC10 are carried out using cruciform specimens. The specimens are deformed under linear loading path on a Zwick/Roell Z010 biaxial tensile testing machine. The maximum equivalent strain attained is 0.02. The loading directions remain coaxial with the plastic orthotropy throughout every experiment. Contours of plastic work in the biaxial stress space are successfully determined and compared with the yield loci calculated from several existing yield criteria. It is found that the yield locus of superalloy IC10 is asymmetric about the balanced biaxial tension line, which indicates strong plastic anisotropy of the material. Von Mises yield criterion fails to describe the plastic anisotropy of IC10 since it contains only one material constant. Hill's quadratic yield criterion underestimates the measured work contours in the neighborhood of balanced biaxial tension. Logan & Hosford's yield criterion underestimates severely the measured work contours from the balanced biaxial tension to transverse uniaxial tension. Banabic-Balan's yield criterion and Barlat's yield criterion fit the data points well, which indicates it can describe the yielding behavior of superalloy IC10 under biaxial tension with good accuracy.

Key words: superalloy IC10, biaxial tensile test, cruciform specimen, plastic anisotropy, yield criterion