Autonomous healing of fatigue cracks via cold welding

Nature (2023)Cite this article

7908 Accesses

1211 Altmetric

Metrics details

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 reversal4,5,6,7,8,9. 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.

This is a preview of subscription content, access via your institution

Access Nature and 54 other Nature Portfolio journals

Get Nature+, our best-value online-access subscription

$29.99 / 30 days

cancel any time

Subscribe to this journal

Receive 51 print issues and online access

$199.00 per year

only $3.90 per issue

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

The datasets generated and/or analysed during the current study are available from the corresponding author on reasonable request.

Suresh, S. Fatigue of Materials (Cambridge Univ. Press, 2001).

Pan, Q., Zhou, H., Lu, Q., Gao, H. & Lu, L. History-independent cyclic response of nanotwinned metals. Nature 551, 214–217 (2017).

Article ADS CAS PubMed Google Scholar

Kruzic, J. J. Predicting fatigue failure. Science 325, 156–158 (2009).

Article CAS PubMed Google Scholar

Li, C. H. et al. A highly stretchable autonomous self-healing elastomer. Nat. Chem. 8, 618–624 (2016).

Article ADS CAS PubMed Google Scholar

Toohey, K. S., Sottos, N. R., Lewis, J. A., Moore, J. S. & White, S. R. Self-healing materials with microvascular networks. Nat. Mater. 6, 581–585 (2007).

Article CAS PubMed Google Scholar

Urban, M. W. Key-and-lock commodity self-healing copolymers. Science 362, 220–225 (2018).

Article ADS CAS PubMed Google Scholar

Hager, M. D., Greil, P., Leyens, C., van der Zwaag, S. & Schuber, U. S. Self-healing materials. Adv. Mater. 22, 5424–5430 (2010).

Article CAS PubMed Google Scholar

Li, X. et al. Mesoscale bicontinuous networks in self-healing hydrogels delay fatigue fracture. Proc. Natl Acad. Sci. USA 117, 7606–7612 (2020).

Article ADS CAS PubMed PubMed Central Google Scholar

Patrick, J. F., Robb, M. J., Sottos, N. R., Moore, J. S. & White, S. R. Polymers with autonomous life-cycle control. Nature 540, 363–370 (2016).

Article ADS CAS PubMed Google Scholar

Koyama, M. et al. Bone-like crack resistance in hierarchical metastable nanolaminate steels. Science 355, 1055–1057 (2017).

Article ADS CAS PubMed Google Scholar

Cheng, Z., Zhou, H., Lu, Q., Gao, H. & Lu, L. Extra strengthening and work hardening in gradient nanotwinned metals. Science 362, eaau1925 (2018).

Article ADS PubMed Google Scholar

Munch, E. et al. Tough, bio-inspired hybrid mateirals. Science 322, 1516 (2008).

Article ADS CAS PubMed Google Scholar

Suresh, S. Crack deflection: implications for the growth of long and short fatigue cracks. Metall. Trans. A 14A, 2375 (1983).

Article ADS Google Scholar

Fang, H. et al. Self healing of creep damage in iron-based alloys by supersaturated tungsten. Acta Mater. 166, 531–542 (2019).

Article ADS CAS Google Scholar

van Dijk, N. & van der Zwaag, S. Self-healing phenomena in metals.Adv. Mater. Interfaces 5, 1800226 (2018).

Article Google Scholar

Leeuwenburgh, S. C. G., De Belie, N. & van der Zwaag, S. Self-healing materials are coming of age.Adv. Mater. Interfaces 5, 1800736 (2018).

Article Google Scholar

Wang, Y. et al. Self-healing of fractured GaAs nanowires. Nano Lett. 11, 1546–1549 (2011).

Article ADS CAS PubMed Google Scholar

Manuel, M. V. in Self‐Healing Materials: Fundamentals, Design Strategies, and Applications (ed. Swapan, K. G.) 251–263 (Wiley-VCH, 2008).

Fisher, C. R. et al. Repairing large cracks and reversing fatigue damage in structural metals. Appl. Mater. Today 13, 64–68 (2018).

Article Google Scholar

Xu, G. & Demkowicz, M. J. Crack healing in nanocrystalline palladium. Extreme Mech. Lett. 8, 208–212 (2016).

Article Google Scholar

Xu, G. Q. & Demkowicz, M. J. Healing of nanocracks by disclinations. Phys. Rev. Lett. 111, 145501 (2013).

Article ADS CAS PubMed Google Scholar

Suresh, S., Zamiski, G. F. & Ritchie, R. O. Oxide induced crack closure: an explanation for near-threshold corrosion fatigue crack growth behavior. Metall. Trans. A 12A, 1435–1443 (1981).

Article ADS Google Scholar

Suresh, S. & Ritchie, R. O. A geometric model for fatigue crack closure induced by fracture surface roughness. Mater. Sci. Eng. A 150, 209–212 (1982).

Google Scholar

Suresh, S. & Ritchie, R. O. Near Threshold Fatigue Crack Propagation: A Perspective on the Role of Crack Closure Report No. LBL-16263 (Lawrence Berkeley Lab., 1983).

Randle, V. An investigation of grain-boundary plane crystallography in polycrystalline nickel. J. Mater. Sci. 30, 3983–3988 (1995).

Article ADS CAS Google Scholar

Randle, V., Caul, M. & Fiedler, J. Twinning and interfacial planes in copper. Microsc. Microanal. 3, 224–233 (2003).

Article ADS Google Scholar

Ke, X. et al. Ideal maximum strengths and defect-induced softening in nanocrystalline-nanotwinned metals. Nat. Mater. 18, 1207–1214 (2019).

Article ADS CAS PubMed Google Scholar

Wang, Y. M. et al. Defective twin boundaries in nanotwinned metals. Nat. Mater. 12, 697–702 (2013).

Article ADS CAS PubMed Google Scholar

Hirth, J. P., Wang, J. & Tomé, C. N. Disconnections and other defects associated with twin interfaces. Prog. Mater. Sci. 83, 417–471 (2016).

Article Google Scholar

Dai, G., Wang, B., Xu, S., Lu, Y. & Shen, Y. Side-to-side cold welding for controllable nanogap formation from “dumbbell” ultrathin gold nanorods. ACS Appl. Mater. Interfaces 8, 13506–13511 (2016).

Article CAS PubMed Google Scholar

Ferguson, G. S., Chaudhury, M. J., Sigal, G. B. & Whitesides, G. M. Contact adhesion of thin gold films on elastomeric supports: cold welding under ambient conditions. Science 253, 776–778 (1991).

Article ADS CAS PubMed Google Scholar

Lu, Y., Huang, J. Y., Wang, C., Sun, S. & Lou, J. Cold welding of ultrathin gold nanowires. Nat. Nanotechnol. 5, 218–224 (2010).

Article ADS CAS PubMed Google Scholar

Wagle, D. V. & Baker, G. A. Cold welding: a phenomenon for spontaneous self-healing and shape genesis at the nanoscale. Mater. Horizons 2, 157–167 (2015).

Article CAS Google Scholar

Thomas, S. L., Wei, C., Han, J., Xiang, Y. & Srolovitz, D. J. Disconnection description of triple-junction motion. Proc. Natl Acad. Sci. USA 116, 8756–8765 (2019).

Article ADS MathSciNet CAS PubMed PubMed Central MATH Google Scholar

Bufford, D. C. et al. High cycle fatigue in the transmission electron microscope. Nano Lett. 16, 4946–4953 (2016).

Article ADS CAS PubMed Google Scholar

Sarkar, R., Rentenberger, C. & Rajagopalan, J. Electron beam induced artifacts during in situ TEM deformation of nanostructured metals. Sci. Rep. 5, 16345 (2015).

Article ADS CAS PubMed PubMed Central Google Scholar

Raabe, D., Sachtleber, M., Zhao, Z., Roters, F. & Zaefferer, S. Micromechanical and macromechanical effects in grain scale polycrystal plasticity experimentation and simulation. Acta Mater. 49, 3433–3441 (2001).

Article ADS CAS Google Scholar

Lim, H. et al. Grain-scale experimental validation of crystal plasticity finite element simulations of tantalum oligocrystals. Int. J. Plast. 60, 1–18 (2014).

Article CAS Google Scholar

Cahn, J. W., Mishin, Y. & Suzuki, A. Coupling grain boundary motion to shear deformation. Acta Mater. 54, 4953–4975 (2006).

Article ADS CAS Google Scholar

Mompiou, F., Caillard, D. & Legros, M. Grain boundary shear–migration coupling. I. In situ TEM straining experiments in Al polycrystals. Acta Mater. 57, 2198–2209 (2009).

Article ADS CAS Google Scholar

Ferguson, G. S., Chaudhury, M. K., Sigal, G. B. & Whitesides, G. M. Contact adhesion of thin gold films on elastomeric supports: cold welding under ambient conditions. Science 253, 776–778 (1991).

Article ADS CAS PubMed Google Scholar

Kim, C., Burrows, P. E. & Forrest, S. R. Micropatterning of organic electronic devices by cold-welding. Science 288, 831–833 (2000).

Article ADS CAS PubMed Google Scholar

Baumert, E. K., Sadeghi-Tohidi, F., Hosseinian, E. & Pierron, O. N. Fatigue-induced thick oxide formation and its role on fatigue crack initiation in Ni thin films at low temperatures. Acta Mater. 67, 156–167 (2014).

Article ADS CAS Google Scholar

Maierhofer, J., Simunek, D., Gänser, H.-P. & Pippan, R. Oxide induced crack closure in the near threshold regime: the effect of oxide debris release. Int. J. Fatigue 117, 21–26 (2018).

Article CAS Google Scholar

Moore, A. J. W. Deformation of metals in static and in sliding contact. Proc. R. Soc. A 195, 231–244 (1948).

ADS Google Scholar

Wang, Q. et al. Gigacycle fatigue of ferrous alloys. Fatigue Fract. Eng. Mater. Struct. 22, 667–672 (1999).

Article CAS Google Scholar

Snowden, K. U. The effect of atmosphere on the fatigue of lead. Acta Metall. 12, 295–303 (1964).

Article CAS Google Scholar

Boyce, B. L., Michael, J. R. & Kotula, P. G. Fatigue of metallic microdevices and the role of fatigue-induced surface oxides. Acta Mater. 52, 1609–1619 (2004).

Article ADS CAS Google Scholar

Jiang, R. & Reed, P. A. S. Critical Assessment 21: oxygen-assisted fatigue crack propagation in turbine disc superalloys. Mater. Sci. Technol. 32, 401–406 (2016).

Article ADS Google Scholar

Radon, J. A model for fatigue crack growth in a threshold region. Int. J. Fatigue 4, 161–166 (1982).

Article Google Scholar

Pippan, R. & Hohenwarter, A. Fatigue crack closure: a review of the physical phenomena. Fatigue Fract. Eng. Mater. Struct. 40, 471–495 (2017).

Article CAS PubMed PubMed Central Google Scholar

Oguma, H. & Nakamura, T. Fatigue crack propagation properties of Ti–6Al–4V in vacuum environments. Int. J. Fatigue 50, 89–93 (2013).

Article CAS Google Scholar

Wang, Q., Bathias, C., Kawagoishi, N. & Chen, Q. Effect of inclusion on subsurface crack initiation and gigacycle fatigue strength. Int. J. Fatigue 24, 1269–1274 (2002).

Article CAS Google Scholar

Stephens, R., Dubensky, R., Frauen, L. & Wrenn, R. Fatigue Behavior of Molybdenum (Iowa Univ., 1970).

Oh, Y., Cyrankowski, E., Shan, Z. & Asif, S. A. S. Micro/nano-mechanical test system employing tensile test holder with push-to-pull transformer. US patent US-8789425-B2 (2014).

Chisholm, C. et al. Dislocation starvation and exhaustion hardening in Mo alloy nanofibers. Acta Mater. 60, 2258–2264 (2012).

Article ADS CAS Google Scholar

Hattar, K., Bufford, D. C. & Buller, D. L. Concurrent in situ ion irradiation transmission electron microscope. Nucl. Instrum. Methods Phys. Res. Sect. B 338, 56–65 (2014).

Article ADS CAS Google Scholar

Heckman, N. M. et al. New nanoscale toughening mechanisms mitigate embrittlement in binary nanocrystalline alloys. Nanoscale 10, 21231–21243 (2018).

Article CAS PubMed Google Scholar

Ohr, S. M. An electron microscope study of crack tip deformation and its impact on the dislocation theory of fracture. Mater. Sci. Eng. 72, 1–35 (1985).

Article CAS Google Scholar

Christ, H. J., Fritzen, C. P. & Köster, P. Micromechanical modeling of short fatigue cracks. Curr. Opin. Solid State Mater. Sci. 18, 205–211 (2014).

Article ADS Google Scholar

Rauch, E. F. & Véron, M. Automated crystal orientation and phase mapping in TEM. Mater. Charact. 98, 1–9 (2014).

Article CAS Google Scholar

Leff, A. C., Weinberger, C. R. & Taheri, M. L. Estimation of dislocation density from precession electron diffraction data using the Nye tensor. Ultramicroscopy 153, 9–21 (2015).

Article CAS PubMed Google Scholar

Zhou, X. W., Johnson, R. A. & Wadley, H. N. G. Misfit-energy-increasing dislocations in vapor-deposited CoFe/NiFe multilayers.Phys. Rev. B 69, 144113 (2004).

Article ADS Google Scholar

Kung, H. et al. Observation of body centered cubic Cu in Cu/Nb nanolayered composites. Appl. Phys. Lett. 71, 2103–2105 (1997).

Article ADS CAS Google Scholar

Petrov, I., Barna, P. B., Hultman, L. & Greene, J. E. Microstructural evolution during film growth. J. Vacuum Sci. Tech. A Vacuum Surfaces Films 21, S117–S128 (2003).

Article ADS CAS Google Scholar

Plimpton, S. Fast parallel algorithms for short-range molecular dynamics. J. Comput. Phys. 117, 1–19 (1995).

Article ADS CAS MATH Google Scholar

Stukowski, A. Visualization and analysis of atomistic simulation data with OVITO—the Open Visualization Tool. Modelling Simul. Mater. Sci. Eng. 18, 015012 (2010).

Article ADS Google Scholar

Download references

We thank D. Medlin, P. Lu, R. J. Parrish, W. M. Mook, D. D. Stauffer, C. Kunka and R. O. Ritchie for valuable interactions regarding this work. We thank R. Schoell for compiling data collected by Z.M. C.M.B., D.C.B., N.M.H., D.P.A., K.H. and B.L.B. were supported by the US Department of Energy (DOE) Office of Basic Energy Science, Materials Science and Engineering Division. The contributions of T.D. and M.J.D. were supported by the Department of Energy, National Nuclear Security Administration (DE-NA0003857). A.M. and A.S. acknowledge support from the National Science Foundation, Division of Civil, Mechanical, and Manufacturing Innovation (1663130). This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the US DOE Office of Science. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the US DOE National Nuclear Security Administration (DE-NA-0003525). The views expressed in the article do not necessarily represent the views of the US DOE or the US Government.

Khalid Hattar

Present address: Department of Nuclear Engineering, University of Tennessee, Knoxville, TN, USA

Sandia National Laboratories, Albuquerque, NM, USA

Christopher M. Barr, Daniel C. Bufford, Zachary Milne, Nathan M. Heckman, David P. Adams, Khalid Hattar & Brad L. Boyce

Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, USA

Christopher M. Barr, Zachary Milne, Nathan M. Heckman, Khalid Hattar & Brad L. Boyce

Department of Materials Science and Engineering, Texas A&M University, College Station, TX, USA

Ta Duong, Abhilash Molkeri, Ankit Srivastava & Michael J. Demkowicz

You can also search for this author in PubMed Google Scholar

C.M.B., D.C.B., Z.M., N.M.H. and K.H. designed and performed the in situ transmission electron microscope nanocrystalline fatigue investigations. C.M.B., Z.M., N.M.H. and B.L.B. performed the formal analysis of the experimental data and data curation. D.P.A. oversaw the deposition of the nanocrystalline thin-film depositions. T.D. and M.J.D. performed and analysed the molecular dynamic simulations. A.M., A.S. and M.J.D. performed and analysed the finite element simulations. M.J.D. developed the theoretical model of the effect of crack healing on fatigue thresholds. Writing of the original draught was performed by C.M.B., K.H., M.J.D. and B.L.B. All co-authors discussed the results and performed activities in writing, reviewing and editing the manuscript. B.L.B. supervised the project.

Correspondence to Michael J. Demkowicz or Brad L. Boyce.

The authors declare no competing interests.

Nature thanks the anonymous reviewers for their contribution to the peer review of this work. Peer reviewer reports are available.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

(a) crack at new location after monotonic unload after crack healing event, (b–e) crack tip blunting without significant advance at same crack tip location in (a); there is no observation (either from still frames from the video or during monotonic loading/unloading) of the deflected crack being present. In each subfigure, the arrow points to the location of the crack tip. In (e) the apparent appearance of a daughter crack is actually a visual illusion due to transmission imaging, and the video evidence more clearly shows that this crack is connected to the main crack.

Two different realizations of GB34 models: (a) ideal alignment with {111}-type planes in adjacent grains, leading the perfect coherency along the GB plane; (b) GB plane normal to sample surface and ~6.2 degrees offset from ideal {111}-type alignment, resulting in an array of Shockley partial twinning dislocations along the GB plane. (c) Stress-strain curve for a triple junction model with the imperfect CTB shown in (b) loaded in biaxial tension. Tractions on the top and right loading surfaces were computed by adding up the forces on the atoms with fixed y- and x-coordinates in the top and right loading layers, respectively. The response to mechanical loading of the model where the GB34 plane is normal to the sample surface, i.e., ~6.2 degrees offset from ideal {111}-type alignment: (d) as-constructed structure and (e) mechanically-driven GB34 migration after 3% tensile loading in the y-direction (and corresponding level of biaxial loading in the x-direction).

Example of delayed crack healing that occurs when the defected twin boundary is replaced by a perfectly coherent twin boundary: (a) immediately after application of 0.2% tensile loading, (b) onset of closure at the crack tip 100 ps after application of loading, (c) propagation of a front of crack closure, (d) complete crack healing 160 ps after application of loading.

Hydrostatic stresses induced by the triple junction under 0.2% applied tensile strain. This model contains no crack.

(a) Continuum-level version of the triple junction model shown in main text, Fig. 3a. The arrows on the top and bottom surfaces indicate the direction of the tensile axis; (b) the difference in normal displacement of the top and bottom crack faces induced by the non-uniform triple junction stresses in (a). The red contour shows the locus of zero relative crack face displacement. Near the crack tip, the displacement is negative, indicating crack closure.

Once the bonds along GB24 are severed, then migration of GB34 causes a shear in the part of G4 through which the migration has occurred, as shown in (a). The shape of the resulting gap between G2 and G4 is shown in (b). The resultant difference in normal displacement of the top and bottom crack faces induced by migration of GB34 in (a–b). The red contour shows the locus of zero relative crack face displacement. The displacement is negative in a broad region at the crack tip and near one of the free surfaces, indicating a strong tendency toward crack closure.

Observations of crack healing were similar to those observed in nanocrystalline Pt. The sample was loaded with mean load of 152 µN and amplitude of 101 µN at 200 Hz for a 100 s interval. (a) quasi-static image of a mode I crack in the sample after being subjected to 276,000 previous loading cycles, (b) rapid crack deflection by nearly 90° downward from mode I at approximately 278,000 cycles followed by retreat by 288,000 cycles, then (c) propagation at approximately 45° upward from mode I then retreat, followed by (d) propagation by approximately 60° downward again before a third observation of crack retreat before finally (e) returning to normal mode I crack propagation. Outlines of the crack flanks at the maximum extent shown in (b–d) before retreat and propagation in a new direction appears in panel (e). Video of crack deflection, retreat with no signs of crack existing after return to mode-I loading can also be observed in Supplementary Video 3.

(a) Bright field TEM image of free standing nanocrystalline Pt; (b) Nanocrystalline Pt grain size distribution; (c) Overview of experimental push-to-pull device with a nanocrystalline thin film with (d) localized view of an example sample over the push-to-pull gap; (e) example loading sequence where (f) quasi-static loading, (g) dynamic loading at 200 Hz, and (h) quasi-static unloading bright-field TEM images are shown.

(a–b) Observation of fatigue crack initiation where highlights crack path direction; (c) propagation to first grain boundary between G1 and G2 (GB12) where arrow indicates location of crack path; (d) Inverse pole figure coloured orientation map collected at 124,000 total fatigue cycle where the fatigue crack is temporarily arrested.

Crack propagation directions appear commensurate with slip plane traces in Grain 2 (G2).

Supplementary Notes 1–13, Figs. 1–5, Tables 1 and 2, and References.

In situ TEM video of fatigue crack deflection and healing in G2 occurring between fatigue cycles 604,000 and 684,000. The video consists of two full fatigue sequences: dynamic loading between 604,000 cycles to 644,000 cycles and 644,000 to 684,000 cycles. The video also contains the static unloading and loading between these fatigue sequences. In the first sequence, the crack deflects towards the triple junction in G2. In the second sequence, the crack heals. For each fatigue loading sequence, the sample was tested at 200 Hz with 200 seconds of real time cyclic loading. Video is 10× real time speed.

This video provides an animation of the process shown in Fig. 3. Under a static, 0.2% tensile load, the atomistic model containing an imperfect CTB undergoes complete healing.

In situ TEM video of fatigue crack deflection and healing in a nanocrystalline Cu tension sample previously subjected to ≈ 276,000 cycles. Sample was loaded at 152 µN mean load and 101 µN amplitude load at 200 Hz for 100 second dynamic segment (plus quasi-static load and unload segments). Video is in real time.

Monotonic tensile loading of our atomistic model leads to crack tip dislocation emission and crack tip blunting. No crack healing is observed.

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and Permissions

Barr, C.M., Duong, T., Bufford, D.C. et al. Autonomous healing of fatigue cracks via cold welding. Nature (2023). https://doi.org/10.1038/s41586-023-06223-0

Download citation

Received: 27 April 2020

Accepted: 16 May 2023

Published: 19 July 2023

DOI: https://doi.org/10.1038/s41586-023-06223-0

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

News

Autonomous healing of fatigue cracks via cold welding