Damage-tolerant architected materials inspired by crystal microstructure

Architected materials that consist of periodic arrangements of nodes and struts are lightweight and can exhibit combinations of properties (such as negative Poisson ratios) that do not occur in conventional solids. Architected materials reported previously are usually constructed from identical ‘unit cells’ arranged so that they all have the same orientation. As a result, when loaded beyond the yield point, localized bands of high stress emerge, causing catastrophic collapse of the mechanical strength of the material. This ‘post-yielding collapse’ is analogous to the rapid decreases in stress associated with dislocation slip in metallic single crystals. Here we use the hardening mechanisms found in crystalline materials to develop architected materials that are robust and damage-tolerant, by mimicking the microscale structure of crystalline materials—such as grain boundaries, precipitates and phases. The crystal-inspired mesoscale structures  in our architected materials are as important for their mechanical properties as are crystallographic microstructures in metallic alloys. Our approach combines the hardening principles of metallurgy and architected materials, enabling the design of materials with desired properties.Inspired by the enhanced mechanical strength of microstructured metals, damage-tolerant architected materials are developed in which the internal structure is granular, with different regions having different lattice orientations.

[1]  L. Valdevit,et al.  Ultralight Metallic Microlattices , 2011, Science.

[2]  E. Mazza,et al.  Cyclic deformation response of AISI 316L at room temperature: Mechanical behaviour, microstructural evolution, physically-based evolutionary constitutive modelling , 2013 .

[3]  S. Ni,et al.  Atomic-scale understanding of stress-induced phase transformation in cold-rolled Hf , 2017 .

[4]  Marc A. Meyers,et al.  Biological materials: Functional adaptations and bioinspired designs , 2012 .

[5]  Xiaoyu Zheng,et al.  Multiscale metallic metamaterials. , 2016, Nature materials.

[6]  E. Hall,et al.  The Deformation and Ageing of Mild Steel: III Discussion of Results , 1951 .

[7]  M. Buehler,et al.  The mechanics and design of a lightweight three-dimensional graphene assembly , 2017, Science Advances.

[8]  O. Bouaziz,et al.  Heterogeneous and Architectured Materials: A Possible Strategy for Design of Structural Materials , 2008 .

[9]  J. Hirth.  The influence of grain boundaries on mechanical properties , 1972 .

[10]  F. Barthelat,et al.  Architectured materials in engineering and biology: fabrication, structure, mechanics and performance , 2015 .

[11]  Nilesh D. Mankame,et al.  Phase transforming cellular materials , 2015 .

[12]  N. Petch,et al.  The Cleavage Strength of Polycrystals , 1953 .

[13]  J. R. Raney,et al.  Multistable Architected Materials for Trapping Elastic Strain Energy , 2015, Advanced materials.

[14]  F. J. Humphreys,et al.  The deformation of single crystals of copper and copper-zinc alloys containing alumina particles - I. Macroscopic properties and workhardening theory , 1970, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[15]  S. Zapperi,et al.  Dislocation Avalanches, Strain Bursts, and the Problem of Plastic Forming at the Micrometer Scale , 2007, Science.

[16]  M. Ashby,et al.  Cellular solids: Structure & properties , 1988 .

[17]  K. E. Easterling,et al.  Phase Transformations in Metals and Alloys (Revised Reprint) , 2009 .

[18]  P. Imrich,et al.  Differences in deformation behavior of bicrystalline Cu micropillars containing a twin boundary or a large-angle grain boundary , 2014 .

[19]  M. Pham,et al.  Evolution of Relationships Between Dislocation Microstructures and Internal Stresses of AISI 316L During Cyclic Loading at 293 K and 573 K (20 °C and 300 °C) , 2014, Metallurgical and Materials Transactions A.

[20]  R. Armstrong,et al.  The plastic deformation of polycrystalline aggregates , 1962 .

[21]  O. Sigmund,et al.  Design of manufacturable 3D extremal elastic microstructure , 2014 .

[22]  R. Reed.  The Superalloys: Fundamentals and Applications , 2006 .

[23]  A. Argon,et al.  Strengthening Mechanisms in Crystal Plasticity , 2007 .

[24]  A. Cottrell,et al.  Dislocations and plastic flow in crystals , 1953 .

[25]  E. Hall,et al.  The Deformation and Ageing of Mild Steel , 1951 .

[26]  R. Ritchie,et al.  Propagation of short fatigue cracks , 1984 .

[27]  Grace X. Gu,et al.  Printing nature: Unraveling the role of nacre's mineral bridges. , 2017, Journal of the mechanical behavior of biomedical materials.

[28]  S. Tsurekawa,et al.  Effect of grain boundary microstructure on fatigue crack propagation in austenitic stainless steel , 2011 .

[29]  T. Schaedler,et al.  Architected Cellular Materials , 2016 .

[30]  M. Pham,et al.  Role of microstructural condition on fatigue damage development of AISI 316L at 20 and 300 °C , 2013 .

[31]  A. Rollett,et al.  Strength of nanoscale metallic multilayers , 2018 .

[32]  R. Hague,et al.  A mechanical property evaluation of graded density Al-Si10-Mg lattice structures manufactured by selective laser melting , 2016 .

[33]  P. Imrich,et al.  Microcompression and cyclic deformation behaviors of coaxial copper bicrystals with a single twin boundary , 2013 .

[34]  Philip J. Withers,et al.  Influence of processing conditions on strut structure and compressive properties of cellular lattice structures fabricated by selective laser melting , 2015 .

[35]  R. Lakes.  Foam Structures with a Negative Poisson's Ratio , 1987, Science.

[36]  R. Reed.  The Superalloys by Roger C. Reed , 2006 .

[37]  Michael D. Uchic,et al.  Size-affected single-slip behavior of pure nickel microcrystals , 2005 .

[38]  R. Ritchie,et al.  Bioinspired structural materials. , 2014, Nature Materials.

[39]  K. Tsuzaki,et al.  Inverse Temperature Dependence of Toughness in an Ultrafine Grain-Structure Steel , 2008, Science.