Architected material analogs for shape memory alloys

•Architected material analogs of thermally activated shape memory alloys•ASMAs exhibit superelastic behavior and effect•ASMAs undergo stress- temperature-induced phase transformations•We provide a systematic design methodology demonstrate key behaviors for ASMAs Shape alloys (SMAs) are versatile materials that find applications in areas as diverse non-explosive release bolts spacecraft, endodontic files, structural dampers bridges. However, the widespread use these is limited by their high cost, which driven need high-purity raw extensive thermo-mechanical processing. We introduce architected SMAs (ASMAs), periodic cellular both salient behaviors, superelasticity memory, SMAs. They can be made from wide variety polymers, many different low-cost production processes well 3D printing, designed to respond various stimuli such heat, magnetic fields, solvent absorption. offer lower-cost alternative expand space SMA-like include larger-scale (e.g., self-compacting dunnage) or medical implants). propose building block mimics exhibited (SMAs). The comprises sinusoidal beam anchored supports whose storage modulus decreases at faster rate with increasing temperature than beam. At low temperatures, moduli two constituent have comparable magnitudes exhibits stable configurations. transition elastically one configuration other via snap-through response an external load. Above critical temperature, sufficiently second becomes unstable, returns its first without any These responses result ensemble blocks. Architected derive constitutive largely topology blocks distribution within rather chemical composition materials.1Zheludev N.I. road ahead metamaterials.Science. 2010; 328: 582-583Google Scholar,2Fleck N.A. Deshpande V.S. Ashby M.F. Micro-architectured materials: past, present future.Proc. R. Soc. A. Math. Phys. Eng. Sci. 466: 2495-2516Google Scholar Therefore, we properties not found naturally occurring bulk materials. Examples exciting they enabled negative-refractive-index flat loss-less lenses,3Venema L. A lens less ordinary.Nature. 2002; 420: 119-120Google room-temperature terahertz modulators ultra-fast wireless communications,4Chen H.T. Padilla W.J. Zide J.M.O. Gossard A.C. Taylor A.J. Averitt R.D. Active metamaterial devices.Nature. 2006; 444: 597-600Google acoustic negative refraction high-resolution imaging.5Lu M.H. Feng Chen Y.F. Phononic crystals metamaterials.Mater. Today. 2009; 12: 34-42Google Given array been realized materials, it natural wonder if Potential benefits might reduction improvement performance, ability substitute readily available more difficult source. In this work, report development analog class metallic interesting behaviors: effect (SME) (SE).6Wayman C.M. Otsuka K. Memory Alloys. Cambridge University Press, 1998Google SE associated undergoing large, seemingly plastic strains completely recovered upon unloading (see path shown red curves Figure 1F). has exploited strong-yet-flexible instruments root canal treatment7Yoneyama T. Kobayashi C. Endodontic treatment using Ti–Ni alloys.in: Yoneyama Shuichi M. Alloys Biomedical Applications. Woodhead Publishing Limited, Cambridge, UK2009: 297-305Google damage-tolerant eyeglass frames.8Zider R.B. Krumme J.F. Eyeglass frame including elements. US patent 4772112A.1988Google also gives rise large hysteretic losses during cyclic loading, results solid-state energy dissipation. This dissipative used create elements internal dissipation stabilizing sensitive structures like bridges9Wilde Gardoni P. Fujino Y. Base isolation system alloy device elevated highway bridges.Eng. Struct. 2000; 22: 222-229Google buildings.10Song G. Ma N. Li H.N. Applications civil structures.Eng. 28: 1266-1274Google SMAs, SME retain deformed temporary extended periods time subsequently recover original undeformed suitable thermal stimulus blue deployable implantable blood clot filters folded into compact delivery through catheter, unfurled proper location body just letting reach temperature.11Duerig Pelton Stöckel D. An overview nitinol applications.Mater. 1999; 273–275: 149-160Google enables do work against led safer spacecraft deployment12Johnson A.D. No-explosive separation device, 5119555.1992Google highly dexterous endoscopes in-vivo exploration.13Ikuta, K., Tsukamoto, M., Hirose, S. (1988). Alloy Servo Actuator System Electric Resistance Feedback Application Endoscope. 1988 IEEE International Conference on Robotics Automation, pp. 427–430.Google Both arise solid-state, diffusionless transformations between dominant phases material. stress, combination thereof. complexity makes challenging mimic literature survey shows researchers demonstrated some aspects SMA behavior. comprise very coefficients linear expansion (CLTE) embedded actuation exploiting differential level.14Hopkins J.B. Lange K.J. Spadaccini Designing microstructural architectures actuated freedom, actuation, constraint topologies.J. Mech. Des. Trans. ASME. 2013; 135: 061004Google Scholar, 15Xu H. Farag Pasini Thermally hierarchical lattices rotational expansion.J. Appl. 2019; 86: 1-12Google 16Taniker Celli Hofmann D.C. Daraio Temperature-induced morphing bi-metallic structures.Int. J. Sol. 2020; 190: 22-32Google same idea near-zero CLTE.17Lakes Cellular solid unbounded Mater. Lett. 1996; 15: 475-477Google 18Steeves C.A. dos Santos e Lucato S.L. He Antinucci E. Hutchinson J.W. Evans A.G. Concepts structurally robust combine stiffness.J. 2007; 55: 1803-1822Google 19Lehman Lakes Stiff zero Intell. Syst. 2012; 23: 1263-1268Google 20Wei Pei Fang Planar tailorable coefficient stiffness based dual-material triangle unit.J. 2016; 173-191Google 21Boatti Vasios Bertoldi Origami metamaterials tunable expansion.Adv. 2017; 29Google 22Xu Multilevel hierarchy bi-material specific expansion.Acta 134: 155-166Google Like Invar, iron nickel (64FeNi) nearly CLTE, Invar precision scientific where dimensional stability parts needed counteract variations operating temperature. recoverable deformations phase-transforming (PXCMs). PXCMs unit cells instability.23Restrepo Mankame N.D. Zavattieri P.D. Phase transforming materials.Extrem. 2015; 4: 52-60Google When element transforms under load, strain stored released kinetic energy. oscillatory waves dissipate energy, eventually ends up heat.24Findeisen Hohe Kadic Gumbsch Characteristics mechanical buckling elements.J. 102: 151-164Google If sized properly, remain elastic regime loading steps. quasi-static loads,23Restrepo 24Findeisen 25Correa D.M. Seepersad C.C. Haberman M.R. Mechanical honeycomb materials.Integr. Manuf. Innov. 8Google monotonic loads,26Shan Kang S.H. Raney J.R. Wang Candido F. Lewis J.A. Multistable trapping energy.Adv. 27: 4296-4301Google impact loads27Ha C.S. R.S. Plesha M.E. Design, fabrication analysis lattice exhibiting absorption behavior.Mater. 2018; 141: 426-437Google Scholar,28Debeau D.A. Impact materials.J. Res. 33: 290-299Google studied analytical, computational, experimental means recent years. but, unlike cannot permanent stimulus. referenced works above either resistance behavior, but both. Moreover, none build previous research23Restrepo 26Shan 27Ha 28Debeau develop (SE SME) seen term (ASMAs) refer References content provided part supplemental information carry prefix readers section S1.1 list abbreviations symbols work. section, describe how basic PXCM modified introduction ASMA block. beams clamped each end 1A). will referred C1 paper. loaded center figure, undergoes snap-through. attained after C2 According Qiu29Qiu Electrothermally-Actuated Bistable MEMS Relay Power Massachusetts Inst. Technol., 2003: 94Google Scholar,30Qiu Lang J.H. Slocum A.H. curved-beam bistable mechanism.J. Microelectromech. 2004; 13: 137-146Google single parameter Q, ratio amplitude thickness beam, controls C2. Q > 2.31 yields persist indefinitely absence load seeking reverse deformation top row 1A. ? [1.23, 2.31] leads metastable reverts when removed, bottom < 1.23 simple nonlinear spring no force (F)-deflection (d) stack (bistable metastable) connected mechanically series show plateau. plateaus F-d consequence experiences axial compression bending deformation. length shortens moves toward straight line joining ends, increases away line. determined interplay competing sources beam.29Qiu 30Qiu 31Liu Gomez Vella Delayed bifurcation instabilities.J. 2021; 151: 104386Google (Ua) varies non-monotonically deflection serves stabilize S1). On hand, (Ub) monotonically primary driver restoring Thus, Ua promotes bistability while Ub favors metastability compliance determinant Ua. Varying support provides modulate Ua, thus exploit observation two-material variation design; proposed 1B along PXCM.23Restrepo geometry identical. entirely m1. almost m1 well; however, (m2). similar (E) temperatures (TL), E(m1) ? E(m2) higher (Th) schematically 1C. 1D (PXCM) 1E (ASMA). As blocks, Tl. increases, (m2) reduces (m1). relaxes consequently discussed earlier, rises value (Tt), relaxation sufficient switch metastable. changes quantitatively peak Th because E), remains unchanged, whereas qualitatively (C2 unstable) (Th Tt). Unlike was geometric (Q), dependent parameters: (T). allows us endow observed note only behavior; designs presented “Designing constrained recovery.” explore similarities ASMAs. begin establishing equivalence then proceed NiTiNOL, family equi-atomic fractions Ni Ti, canonical reversible phases. austenite (A) high-symmetry cell (cubic, B2) (T Af, finish temperature). martensite lower-symmetry (monoclinic, B19') Mf, temperature), As, start temperature) stress. mentioned diffusionless; i.e., there long-range migration atoms, type takes place small coordinated movements number atoms. main varieties: unstrained (denoted M+/-) de-twinned oriented (M+). Thermal self-accommodating mixture several energetically equivalent variants obtained cooling stress-free condition austenite. Oriented exclusively variant favored applied load.32Shaw, J.A., Churchill, C.B., Lagoudas, D.C., Kumar, (2010). alloys. 1–20. 10.1002/9780470686652.EAE232.Google comprising arranged manner. transitions C2, unchanged cooperative rearrangement repeated throughout all sample reminiscent non-diffusive atoms NiTiNOL. may significantly depending parameters, volume much smaller packed closely together former case. physical having (or vice versa) application removal) accompanied jump involve exchange environment. Based observations, following interpretation PXCMs. C2), said 1 2 respectively). underlying bistable, B name; e.g., B1 C1. Similarly, metastable, M M2 transformation M1) B2 respectively) called forward transformation, opposite direction transformation. 1F schematic showing paths (red lines) (blue equivalents ASMAs, stress-strain-temperature space. Salient points diagram numbered, numbers discussion below. juxtaposed emphasize equivalence. NiTiNOL exists Af. wire (point ? 1F) uniaxial tension T initially, observe nominally until threshold stress reached ?. Beyond level, (M+) thermodynamically favorable, hence, stress-induced M+ move ? ?. completed ? stage. unloaded ?, persists another (lower) crossed ?. lower Hence, segment ?–? path. ?, further recovery over ?–?. overloaded cycle, irreversible wire. Consequently, state ? identical starting Tt. Consider M1 Tt point figure. subjected axis symmetry block, initially see ?–? deform configuration. ?, causes global drop experienced remaining rows still M1. again reaches level snaps through. sequence ripples whole complete, continue beyond (e.g. ?–?), phase. Unloading retracting process continues ?, back entire ? ? manner properly23Restrepo Scholar,29Qiu load-unload process. Further revert ?, ?. serration caused concomitant rows, size relative and, serrations easily visible overall stress-strain response.23Restrepo residual strains, ? below Mf (M+/-) Uniaxial due straining ?. externally alters landscape favor aligned corresponding ?, directions reorienting align de-twinning. ?, past ? ?–?), corresponds unload free ?. ?, existed M+/- phase, There ?, accumulation reorientation de-twinning st