Large recoverable strains with high recovery rates via cooperative regulation of texture and precipitation in additive manufactured NiTi alloy

• Published in: Scripta materialia 2024-07, Vol.248, p.116122, Article 116122
• Main Authors: Yang, C., Huang, Z.Y., Chen, T., Lu, H.Z., Ma, H.W., Li, H.Z., Yan, A., Li, P.X., Hosoda, H., Cai, W.S.
• Format: Article
• Language: English
• Subjects: Additive manufacturing; Precipitation; Shape memory alloys; Texture
• ISSN: 1359-6462; 1872-8456
• DOI: 10.1016/j.scriptamat.2024.116122

We report large recoverable strains with high recovery rates in additive manufactured (AM) Ni51.4Ti48.6 shape memory alloy (SMA), which is accomplished through cooperative regulation of the 〈011〉 texture in B2 austenite matrix by AM and the dispersed coherent Ni4Ti3 nanoprecipitates by post aging. Specifically, the AM and aged sample exhibits high tensile recoverable strain of 5.2 % together with a 100 % recovery rate in stress-assisted temperature-actuation test, and a large recoverable strain of 5.9 % accompanied by a 98 % recovery rate in cyclic superelastic tension. The performances reported here represent the highest levels in various AM NiTi SMAs reported so far. The large recoverable strains stem from the large transformation-related strain of the “soft” 〈011〉 orientation, while the high recovery rate is attributed to the precipitation strengthening of dispersed coherent Ni4Ti3 nanoprecipitates. This successful cooperative regulation in NiTi SMAs underscores its broader potential in AM processing of high-performance metallic materials. [Display omitted]