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Elastic constants and internal friction of martensitic steel, ferritic-pearlitic steel, and α-iron



Sudook A. Kim, Ward L. Johnson


The elastic constants and internal friction of induction hardened and unhardened SAE 1050 plain-carbon steel were determined by acoustic resonance spectroscopy. The hardened specimen contained only martensite and the unhardened specimen was ferrite-pearlite. Using an inverse Ritz algorithm under the assumption of orthorhombic symmetry, all nine independent elements of the elastic-stiffness tensor were determined, and from the resonant peak widths, all nine elements of the internal friction tensor were determined. Similar measurements and analysis on monocrystalline α-iron were performed. The steel was found to be only slightly anisotropic, and the isotropically approximated elastic constants were lower in the martensite than in ferrite-pearlite: shear modulus by 4 %, bulk modulus by 1 %, Young modulus by 3 %, and Poisson ratio by 1.5 %. Isotropically approximated elastic constants and Poisson ratio of ferrite-pearlite and α-iron were similar. All elements of the internal friction tensor in martensite were higher than those of ferrite-pearlite, but lower than those of α-iron.
Mater. Sci. Eng. A


α-iron, bulk modulus, carbon steel, damping, elastic constants, ferrite, hardness, induction hardening, internal friction, martensite, iron, pearlite, Poisson ratio, resonant ultrasound spectroscopy, shear modulus, Young modulus.
Created January 2, 2007, Updated January 27, 2020