Structure-microstructure interactions in compression deformation of NiTi shape memory alloy micropillars

• Published in: Materials letters Vol. 257; no. C; p. 126693
• Main Authors: Paul, Partha P., Kabirifar, Parham, Sun, Qingping, Brinson, L. Catherine
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.12.2019; Elsevier BV; Elsevier
• Subjects: Crystallography; Deformation; Finite element simulations; Grain boundaries; Grain size; Intermetallic compounds; Martensitic transformations; Materials science; Micromechanics; Micropillars; Microstructure; Nickel base alloys; Nickel titanides; Nickel titanium; Phase transformation; Phase transitions; Shape memory alloys; Specimen geometry; Micromechanics; Phase transformation; Shape memory alloys; Finite element simulations; Micropillars; Nickel titanium
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2019.126693

•Micromechanical simulations elucidate structure-microstructure interactions in SMAs.•Deformation is suppressed when grain size(G) ∼ specimen size(D) in SMA micropillars.•Structure: Specimen geometry interaction with grain size is strongest when G ∼ D.•Microstructure: Texture and neighboring grains’ interaction is weaker when G ∼ D.•Strong structural and weak microstructural effects cause lower overall deformation. The interaction between structure and microstructure is studied via compression of NiTi Shape Memory Alloy (SMA) micropillars. In particular, the suppression of phase transformation seen in experiments when the intrinsic grain size approaches the external specimen size is examined through micromechanical simulations. The major factors contributing to this deformation suppression are the intra-grain difference between grain boundaries and interiors, number of nearest neighbors and crystallographic texture interacting with the specimen geometry, as it approaches the average grain size.