Study on notch tensile properties of Fe-Mn-Si shape memory alloy

Abstract

In order to investigate the effect of stress concentration on the mechanical properties of Fe-Mn-Si shape memory alloy, Fe17Mn5Si10Cr5Ni shape memory alloy was selected as the research object in this study. Specimens with different notch types and sizes were designed, and uniaxial tensile tests were conducted on the notched specimens at room temperature. The effects of notch parameters on stress–strain curve, the notch tensile strength, notch sensitivity, and fracture mode were studied. The results indicate that Fe-Mn-Si shape memory alloy is sensitive to notches. V-shaped notch specimens with the same notch radius exhibit stronger ductility and larger fracture strain than U-shaped notch specimens. The tensile strength of the notch increases with the decrease of the notch radius. The stress concentration caused by the notch limits the plastic deformation ability of the material, resulting in significantly lower ductility of the notched specimen compared to the smooth specimen. The presence of notches does not change the tensile fracture type of the alloy, which is ductile fracture. Compared with Q235 steel, Fe-Mn-Si shape memory alloy has better ductility. The stress–strain curve of Q235 steel shows a clear yield plateau and slight hardening behavior, while the yield plateau of Fe-Mn-Si shape memory alloy is not obvious.

Keywords

• Fe-Mn-Si shape memory alloy
• stress concentration
• notch tensile property
• notch sensitivity