Mechanical Properties of σ-Phase and Its Effect on the Mechanical Properties of Austenitic Stainless Steel

In this present paper, the mechanical properties of sigma-phase and its effect on the mechanical properties of 304H austenitic stainless steel after servicing for about 8 years at 680-720 degrees C were studied by nano-indentation test, uniaxial tensile test, and impact test. The results showed that the nano-hardness (H), Young's modulus (E), strain hardening exponent (n), and yield strength (sigma(y)) of sigma-phase were 14.95 GPa, 263 GPa, 0.78, and 2.42 GPa, respectively. The presence of sigma-phase increased the hardness, yield strength, and tensile strength, but greatly reduced the elongation and impact toughness of the material.

Automated summary

This study investigated the mechanical properties and the influence of sigma-phase on 304H austenitic stainless steel. The results showed that the presence of sigma-phase increased the hardness and strength of the material, but decreased its ductility and impact toughness.