Tension-Compression Asymmetry of Superelasticity in Unidirectionally Solidified Cu-Al-Mn Shape Memory Alloy

The unidirectionally solidified Cu-Al-Mn shape memory alloy with strong -oriented texture along the solidification direction and high length-diameter ratio columnar-grained structure exhibits excellent superelastic properties compared to the Ni-Ti alloys. In this paper, the tension-compression asymmetry of unidirectionally solidified Cu71Al18Mn11 alloy was researched by the geometrically nonlinear theory and superelastic experiments. The results show that the tension-compression asymmetry of the alloy has a significant anisotropy. The theoretical asymmetry ratio of transformation strain along reaches 14.2%, which is larger than other orientations. The tension and compression superelastic experiment research of unidirectionally solidified Cu71Al18Mn11 SMA along the direction parallel ( grain orientation) or perpendicular (- grain orientation) to the solidification direction indicates that their superelastic strain, transformation strain, elastic modulus, transformation platform slope, and critical stress have obvious tension-compression asymmetry.