Abstract
Reports on the constitutive modeling during elevated temperature deformation of multi-principal-element alloys (MPEA) are scant and the correlation of constitutive relationships with the established creep theories remained to be unraveled. In response, in the present work, the high-temperature constitutive behavior of a new MPEA containing Sn, Zn, Cu, Al, and Mg was studied based on the hot compression tests. In the microstructure of the alloy, β-Sn as the matrix phase along with the Zn, α-Al, Mg2Sn, and Al4.2Cu3.2Zn0.7 phases were observed. The deformation activation energy was found to be near the lattice self-diffusion activation energy of β-Sn (108.9 kJ/mol). However, basic constitutive analysis resulted in the stress exponents of ~15.5, which was related to the interference of other phases with the hot deformation mechanism in this alloy. Via consideration of a threshold stress (σth), and proposing a unique method for calculation of σth, the stress exponent of ~5 was obtained. Based on creep theories, the glide and climb of dislocations in the climb-controlled regime was found to be responsible for hot deformation of this alloy. Accordingly, a reliable and physically-based constitutive equation was proposed for prediction of hot flow stress.
Published Version
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