Low‐Energy Room‐Temperature Healing of Cellular Metals

Abstract

Healing metallic materials involves high temperatures and large energy inputs. This work demonstrates rapid, effective, low-energy, and roomtemperature healing of metallic materials by using electrochemistry and polymer-coated cellular nickel to mimic the transport-mediated healing of bone. The polymer coating enables selective healing only at the fracture site, electrochemical reactions transport metal ions from a metal source to fractured areas, and the cellular structure of the metal allows facile ion transport to healing sites and effective recovery of strength and toughness when the cellular metal is subjected to three types of damage (scission fracture, tensile failure, and plastic deformation). Using this strategy, samples fractured in tension and by scission recover 100% of their tensile strength in as little as 10 and 4 h of healing. The healing process is stochastic, thus a statistical method is used to quantify and predict the likelihood of achieving target healing strengths based on energy input. This electrochemistry-based approach enables the first demonstration of room-temperature healing of structural metallic materials and requires several orders of magnitude less energy than many previously reported metal healing techniques.

Low energy repair of co-continuous metal-ceramic composites using electrodeposition

“…The energy consumption per crack length for nickel foam was reported to be 200 À 500 J mm . 12 In our case, we locally healed the crack as opposed to submerging the entire sample into an electrolyte bath, which can explain the much smaller energy consumption in our process. Specifically, our results show that the energy input per unit length of crack to heal the crack was three orders of magnitude lower than the reported value for nickel foams.…”

“…In this process, desired metal structures were coated with a polymer layer, and after fracture, they were submerged into an electrolyte bath to deposit metal at cracked regions to heal the samples. 11,12 Metal-ceramic composites are advanced composites that consist of a metallic matrix reinforced with materials including ceramic materials most commonly alumina and silicon carbide in continuous fiber, short fiber, whisker, and micro-platelets forms, as well as carbon fibers. 13,14 Because of high specific strength, stiffness, and elastic modulus, in addition to remarkable fracture toughness, metal-ceramic composites are used in aircraft structures such as landing gears, high-performance and light-weight structural composites, engine components, wear-resistance parts, and cutting tools for advanced manufacturing of aerospace parts.…”

Materials with Electroprogrammable Stiffness

“…Electrochemistry has been extensively used to produce chemicals, manufacture and modify materials, and realize energy sources. [ 137–141 ] Here, we discuss how electrically driven chemical changes have been used to program stiffness changes in ionoprinted hydrogels, electroplastic elastomer hydrogels (EPEHs), and electrochemically reconfigurable microlattices. Finally, we detail the implementations of these electrochemical materials in reconfigurable actuators and self‐assembling structures, and how material selection and properties are critical to realizing fast, large, and programmable stiffness changes in electrochemical systems.…”

A Review of Self-healing Metals: Fundamentals, Design Principles and Performance

“…7 [54]. Wang et al applied electropulsing as extrinsic energy to heal the microcrack via a process of currents redistribution, which resulted in a thermal and compressive stress concentration around crack, driving atom flow to close cracks tips [55,56].…”

“…Reprinted with permission from Ref. [54] Fig. 8 Distortion and self-healing of coherent twin boundaries (CTBs).…”