Phase transformation volume amplitude as a low-cycle fatigue indicator in nickel-titanium shape memory alloys

SCRIPTA MATERIALIA

卷:178

Article

Paranjape, Harshad M.¹  Ng, Bill¹  Ong, Ich¹  Vien, Lot¹  Huntley, Christopher¹ 

[1] Confluent Med Technol Inc, 47533 Westinghouse Dr, Fremont, CA 94539 USA

关键词: NiTi;    Shape memory alloys;    Fatigue;    Digital image correlation;   

DOI  :  10.1016/j.scriptamat.2019.12.014

来源: Elsevier

【 摘 要 】

Transformation-induced plasticity due to the motion of martensite fronts is a key mechanism for damage accumulation during cyclic loading of NiTi shape memory alloys (SMAs). Intuitively, a larger motion of martensite fronts should result in a larger accumulation of defects, and lead to a shorter low-cycle fatigue life. We validate this hypothesis through fatigue tests and surface strain-field measurements. This result is agnostic of the tensile or bending loading mode. We also demonstrate that the fatigue lifetime intrinsically depends on a combination of two factors: The transformation volume amplitude and the number of inclusions interacting with the phase transformation domains. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd.

【 授权许可】

Free