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Barr CM, Duong T, Bufford DC, Milne Z, Molkeri A, Heckman NM, Adams DP, Srivastava A, Hattar K, Demkowicz MJ, Boyce BL. Autonomous healing of fatigue cracks via cold welding. Nature 2023; 620:552-556. [PMID: 37468631 DOI: 10.1038/s41586-023-06223-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 05/16/2023] [Indexed: 07/21/2023]
Abstract
Fatigue in metals involves gradual failure through incremental propagation of cracks under repetitive mechanical load. In structural applications, fatigue accounts for up to 90% of in-service failure1,2. Prevention of fatigue relies on implementation of large safety factors and inefficient overdesign3. In traditional metallurgical design for fatigue resistance, microstructures are developed to either arrest or slow the progression of cracks. Crack growth is assumed to be irreversible. By contrast, in other material classes, there is a compelling alternative based on latent healing mechanisms and damage reversal4-9. Here, we report that fatigue cracks in pure metals can undergo intrinsic self-healing. We directly observe the early progression of nanoscale fatigue cracks, and as expected, the cracks advance, deflect and arrest at local microstructural barriers. However, unexpectedly, cracks were also observed to heal by a process that can be described as crack flank cold welding induced by a combination of local stress state and grain boundary migration. The premise that fatigue cracks can autonomously heal in metals through local interaction with microstructural features challenges the most fundamental theories on how engineers design and evaluate fatigue life in structural materials. We discuss the implications for fatigue in a variety of service environments.
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Affiliation(s)
- Christopher M Barr
- Sandia National Laboratories, Albuquerque, NM, USA
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, USA
| | - Ta Duong
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, USA
| | | | - Zachary Milne
- Sandia National Laboratories, Albuquerque, NM, USA
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, USA
| | - Abhilash Molkeri
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, USA
| | - Nathan M Heckman
- Sandia National Laboratories, Albuquerque, NM, USA
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, USA
| | | | - Ankit Srivastava
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, USA
| | - Khalid Hattar
- Sandia National Laboratories, Albuquerque, NM, USA
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, USA
- Department of Nuclear Engineering, University of Tennessee, Knoxville, TN, USA
| | - Michael J Demkowicz
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, USA.
| | - Brad L Boyce
- Sandia National Laboratories, Albuquerque, NM, USA.
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, USA.
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Cooper MA, Oliver MS, Bufford DC, White BC, Lechman JB. Compression behavior of microcrystalline cellulose spheres: Single particle compression and confined bulk compression across regimes. POWDER TECHNOL 2020. [DOI: 10.1016/j.powtec.2020.06.089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Schindelholz EJ, Spoerke ED, Nguyen HD, Grunlan JC, Qin S, Bufford DC. Extraordinary Corrosion Protection from Polymer-Clay Nanobrick Wall Thin Films. ACS Appl Mater Interfaces 2018; 10:21799-21803. [PMID: 29912546 DOI: 10.1021/acsami.8b05865] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Metals across all industries demand anticorrosion surface treatments and drive a continual need for high-performing and low-cost coatings. Here we demonstrate polymer-clay nanocomposite thin films as a new class of transparent conformal barrier coatings for protection in corrosive atmospheres. Films assembled via layer-by-layer deposition, as thin as 90 nm, are shown to reduce copper corrosion rates by >1000× in an aggressive H2S atmosphere. These multilayer nanobrick wall coatings hold promise as high-performing anticorrosion treatment alternatives to costlier, more toxic, and less scalable thin films, such as graphene, hexavalent chromium, or atomic-layer-deposited metal oxides.
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Affiliation(s)
- Eric J Schindelholz
- Materials Science and Engineering , Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
| | - Erik D Spoerke
- Materials Science and Engineering , Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
| | - Hai-Duy Nguyen
- Materials Science and Engineering , Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
| | - Jaime C Grunlan
- Department of Materials Science and Engineering , Texas A&M University , College Station , Texas 77843 , United States
| | - Shuang Qin
- Department of Materials Science and Engineering , Texas A&M University , College Station , Texas 77843 , United States
| | - Daniel C Bufford
- Materials Science and Engineering , Sandia National Laboratories , Albuquerque , New Mexico 87185 , United States
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Abstract
One of the most common causes of structural failure in metals is fatigue induced by cyclic loading. Historically, microstructure-level analysis of fatigue cracks has primarily been performed post mortem. However, such investigations do not directly reveal the internal structural processes at work near micro- and nanoscale fatigue cracks and thus do not provide direct evidence of active microstructural mechanisms. In this study, the tension-tension fatigue behavior of nanocrystalline Cu was monitored in real time at the nanoscale by utilizing a new capability for quantitative cyclic mechanical loading performed in situ in a transmission electron microscope (TEM). Controllable loads were applied at frequencies from one to several hundred hertz, enabling accumulations of 10(6) cycles within 1 h. The nanometer-scale spatial resolution of the TEM allows quantitative fatigue crack growth studies at very slow crack growth rates, measured here at ∼10(-12) m·cycle(-1). This represents an incipient threshold regime that is well below the tensile yield stress and near the minimum conditions for fatigue crack growth. Evidence of localized deformation and grain growth within 150 nm of the crack tip was observed by both standard imaging and precession electron diffraction orientation mapping. These observations begin to reveal with unprecedented detail the local microstructural processes that govern damage accumulation, crack nucleation, and crack propagation during fatigue loading in nanocrystalline Cu.
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Affiliation(s)
- Daniel C Bufford
- Sandia National Laboratories , Albuquerque, New Mexico 87185, United States
| | | | - William M Mook
- Sandia National Laboratories , Albuquerque, New Mexico 87185, United States
| | - S A Syed Asif
- Hysitron, Inc., Eden Prairie, Minnesota 55344, United States
| | - Brad L Boyce
- Sandia National Laboratories , Albuquerque, New Mexico 87185, United States
| | - Khalid Hattar
- Sandia National Laboratories , Albuquerque, New Mexico 87185, United States
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