Crack Initiation Angle in Single Crystal Shape Memory Alloys

• Published in: Shape memory and superelasticity : advances in science and technology Vol. 9; no. 3; pp. 427 - 436
• Main Authors: Mutlu, Fatma, Anlaş, Günay, Şehitoğlu, Hüseyin
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-09-2023; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Crack initiation; Energy release rate; Finite element method; Martensite; Martensitic transformations; Materials Science; Shape memory alloys; Single crystals; Strain energy; Technical Article; Single Crystal CoNiAl; Crack Initiation Angle; Finite Elements; Anisotropy; Shape Memory Alloys
• ISSN: 2199-384X; 2199-3858
• DOI: 10.1007/s40830-023-00439-9

In this work, the crack initiation angle from a notch in a single crystal shape memory alloy is discussed in detail. Three edge-notched single crystal CoNiAl specimens are tested under similar conditions to observe the crack initiation from the notch, and crack initiations at angles of 43 ± 1° are seen. The initiation angles are then calculated analytically using Generalized Maximum Tangential Stress (GMTS), and Maximum Energy Release Rate (MERR) criteria; the Strain Energy Density (SED) is plotted around the notch. Single edge-notched specimens are also modeled using ABAQUS. First the specimen is loaded up to austenite to martensitic transformation stress followed by further elastic loading of martensite. The results that are obtained analytically, and using Finite Elements (FE) are compared to the experimental ones, and a good agreement is seen.