Grain size effects on NiTi shape memory alloy fatigue crack growth

LePage, William S.; Ahadi, Aslan; Lenthe, William C.; Sun, Qinglei; Pollock, Tresa M.; Shaw, John A.; Daly, Samantha

doi:10.1557/jmr.2017.395

Cited by 41 publications

(17 citation statements)

References 45 publications

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“…A material's resistance to repeated cycles of loading is also known as fatigue capacity, which may be categorized into different types based primarily on the characteristics of the material [41]. Fatigue in NiTi SMAs can be attributed to consecutive cycles of thermomechanical phase transformations [42]. As noted by Humbeeck [43], fatigue in NiTi SMAs can be subdivided into three groups; classic (structural) fatigue that ends with the crack propagation failure, thermal cycling fatigue, and degradation (functional) fatigue.…”

Section: Fatigue Types In Niti Smasmentioning

confidence: 99%

“…Functional fatigue or shakedown can be defined as the progressive deterioration of the SE reactivity i.e. functional degradation due to an increase in dislocation density [42,44]. From a stress perspective, functional fatigue transpires if the sum of the residual and applied stress is greater than the critical stress during martensitic transformation [45].…”

Section: Fatigue Types In Niti Smasmentioning

confidence: 99%

“…From a stress perspective, functional fatigue transpires if the sum of the residual and applied stress is greater than the critical stress during martensitic transformation [45]. Furthermore, residual strain, change in transformation temperature, and hysteresis or lower dissipated energy all represents symptoms of functional fatigue [42]. Conversely, structural fatigue concerns failure that starting from crack initiation, through crack propagation, and ending with ultimate fracture or separation.…”

Section: Fatigue Types In Niti Smasmentioning

confidence: 99%

“…Conversely, structural fatigue concerns failure that starting from crack initiation, through crack propagation, and ending with ultimate fracture or separation. The unique chemical composition of NiTi SMAs and their sensitivity to temperature fluctuations [46], impurity level [38], and machining make structural fatigue in NiTi SMAs affected by many thermomechanical and plastic factors along with interaction of martensitic detwinning or stress-induced martensite (SIM) [42,44,47,48].…”

Section: Fatigue Types In Niti Smasmentioning

confidence: 99%

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On the Fatigue Behavior of Nanocrystalline NiTi Shape Memory Alloys: A Review

Ashbli¹,

Menzemer²

2019

J Nanomed Nanotechnol

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This paper presents a review of the research on the fatigue performance of superelastic polycrystalline nanocrystalline NiTi shape memory alloys (nc NiTi SMAs). A brief introduction to some focal definitions and basic concepts of fatigue measurement and response in NiTi SMAs were given. Results found in the literature on fatigue in nc NiTi SMAs are discussed. Mechanical behavior and energy dissipation capacity of nc NiTi SMAs are explored and collectively compared with coarse-grained NiTi SMAs, along with an assessment of the influence of grain size refinement and thermomechanical treatments. Several conclusions and suggestions are made, including that nc NiTi SMAs exhibit larger functional fatigue resistance, lower crack tolerance, higher superelasticity, and smaller hysteresis loss.

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Section: Fatigue Types In Niti Smasmentioning

confidence: 99%

Section: Fatigue Types In Niti Smasmentioning

confidence: 99%

Section: Fatigue Types In Niti Smasmentioning

confidence: 99%

Section: Fatigue Types In Niti Smasmentioning

confidence: 99%

See 2 more Smart Citations

On the Fatigue Behavior of Nanocrystalline NiTi Shape Memory Alloys: A Review

Ashbli¹,

Menzemer²

2019

J Nanomed Nanotechnol

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“…In this context, recent studies have been made to evaluate some microstructural effects on the crack growth and fatigue life such as the effect of downsizing inclusions [8], grain size [9] and grain orientation around stress concentrators [10] as well as attempts to obtain analytical models to describe the non-linear fatigue behavior of these materials [11,12]. Previous works by these authors [13,14] have studied the effect of heat-treatments in different temperatures in a commercially available superelastic wire and it has been observed that the ones that promote precipitation of coherent Ti 3 Ni 4 particles and the formation of the R-phase in the working temperature provide good fatigue resistance in low-cycle fatigue.…”

Section: Introductionmentioning

confidence: 99%

Effect of the initial phase constitution in the low-cycle fatigue of NiTi wires

Silva

Buono

2019

SN Appl. Sci.

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Vastly used due to their functional properties, NiTi shape memory alloys have mechanical properties and fatigue resistance known to be strongly affected by their thermomechanical state. In this work, the goal was to evaluate the fatigue resistance of near equiatomic Ni-rich NiTi heat treated wires in different tests temperature. In this manner, it was possible to evaluate the phase constitution effect on the fatigue resistance with a fixed thermomechanical condition. For that, a heat treatment at 500 °C for 30 min was performed in initially superelastic wires in an argon atmosphere. DSC tests were performed in order to obtain the transformation temperatures and there different fatigue test temperatures were chosen according to the phase stability ranges. Rotating-bending fatigue tests took place in proper equipment at 4% maximum strain, evaluating the properties of structures constituted by the R-phase, austenite and R-phase + austenite, in each selected test temperature. The results showed that the R-phase presents higher low-cycle fatigue resistance than austenite and a fatigue mechanism was proposed.

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Nickel–Titanium Alloy Laser Micromachining: A Review of Nitinol Laser Processes and Optimization for High‐Speed Laser Cutting

Otto,

Vaseghi,

Davami

2024

Adv Eng Mater

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The nickel‐titanium (NiTi) alloy, “Nitinol”, has become a prominent name in the medical device industry amongst medical device manufacturers. The unique properties of the material, such as the shape memory effect and pseudoelasticity, have earned the material increasing popularity for new product innovations. Amongst the various manufacturing processes for metal alloys, laser micromachining has taken the lead for processing Nitinol‐based products. This literature review provides an analysis of the history and applications of Nitinol, an overview of the microstructure of the material, and a review of the current manufacturing methods for laser cutting medical‐grade Nitinol. A more in‐depth focus is placed on the realm of laser processing and the challenges associated with the manufacturing process. Ultrafast femtosecond pulse processing delivers promising results and quality for manufacturing Nitinol medical devices. However, there exists a need to investigate potential approaches to increase the cutting speed of the process to enhance throughput and stay competitive in a growing market due to the cutting speed being over 4‐times slower than long pulse cutting. Many tactics to address the problem are discussed, ranging from laser selection, processing parameters, and non‐traditional laser processing approaches.This article is protected by copyright. All rights reserved.

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Grain size effects on NiTi shape memory alloy fatigue crack growth

Abstract: Abstract

Cited by 41 publications

References 45 publications

On the Fatigue Behavior of Nanocrystalline NiTi Shape Memory Alloys: A Review

On the Fatigue Behavior of Nanocrystalline NiTi Shape Memory Alloys: A Review

Effect of the initial phase constitution in the low-cycle fatigue of NiTi wires

Nickel–Titanium Alloy Laser Micromachining: A Review of Nitinol Laser Processes and Optimization for High‐Speed Laser Cutting

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