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The effect of the grain boundary (GB) misorientation on plastic deformation of Inconel 718 (IN718) alloy was investigated in this paper, using in-situ tensile experiment at 650 °C in combination with crystal plasticity finite element method (CPFEM). The results indicate that dislocations tend to accumulate at GBs to form stress concentration, but the degree of stress concentration does not necessarily increase with the increase of the GB misorientation. It is attributed to the slip transfer at the GBs, determined by the angle between the slip systems of the two adjacent grains. There is a significant uncertainty in the slip transfer for GB misorientation larger than 10°. However, the m α β ′ SF α + SF β criterion, which is a function of the Luster and Morris m α β ′ combining the Schmid factors of the two slip systems with the GB misorientation, has some statistical separation significance. Slip transfer tends to appear at GB misorientation less than 30° and m α β ′ SF α + SF β > 0.78 . This study clarifies the mechanism of the influence of GB misorientation on IN718 microplastic deformation and provides a new strategy to study the deformation behavior of superalloys. [ABSTRACT FROM AUTHOR]

Understanding the plastic behavior of crack tips is crucial for improving the fracture toughness of nanometals. Although many studies are carried out, most previous studies focus on pure metals, and how the crack tip accommodates the plastic deformation of highly concentrated solid‐solution alloys is unclear owing to a lack of direct atomic‐scale evidence. In this study, the atomic‐scale plastic behavior of the crack tip in face‐centered cubic (FCC) AuCu alloy nanocrystals is observed in situ, which provides direct evidence that plastic deformation is governed by the generation of deformation twins and hexagonal close‐packed (HCP) 2H and 4H phases, recurrence of reversible FCC‐HCP phase transitions, and detwinning, which are rarely observed in pure metals. This unusual behavior originates from the inherent chemical inhomogeneity of the AuCu alloy, which inhibits twin thickening via partial dislocations on the adjacent plane, instead of random generation of deformation twins, phase transitions, and reversible processes. This naturally implies a similar behavior at the crack tip in other highly concentrated solid‐solution alloys, including high‐medium‐entropy alloys, providing important insights that greatly improve the understanding of the fracture toughness of metallic materials. [ABSTRACT FROM AUTHOR]

In this paper, the deformation behavior of a nickel-based single-crystal superalloy with [ 1 ¯ 40] and [ 3 ¯ 40] orientations was studied at room temperature by in situ electron backscattered diffraction (EBSD) tensile equipment. The mechanical properties, slip behavior and the corresponding Schmidt factor were analyzed. The deformation bands generated during the plastic deformation stage were found and characterized by using the electron backscattered diffraction (EBSD) technique. Furthermore, the formation and propagation of deformation bands played a softening effect on stress–strain curves; however, the secondary slip bands occurring after the propagation of deformation bands played a hardening effect. Finally, the formation of deformation band and its propagation on the mechanical properties are discussed. [ABSTRACT FROM AUTHOR]

To reveal if universal rules may exist in face centered cubic (FCC) concentrated solid solution (CSS) alloys for strength and plastic deformation at room and cryogenic temperatures, we select a FCC CSS superalloy Haynes 188 to demonstrate the deformation mechanisms from atomic to micrometer scales. In FCC CSS alloys, the yield strength (YS) is intrinsically determined by atomic/modulus mismatches and affected extrinsically by grain size; the tensile strength and elongation to fracture (EF) are governed by the plastic process where low stacking fault energy is beneficial. Moreover, almost all CSS alloys show that YS and EF increase simultaneously with the decrease in the temperature. Our findings may expand alloy application and can be used as a design strategy for stronger and tougher alloys. [ABSTRACT FROM AUTHOR]

Non-conservative dislocation climb plays a unique role in the plastic deformation and creep of crystalline materials. Nevertheless, the underlying atomic-scale mechanisms of dislocation climb have not been explored by direct experimental observations. Here, we report atomic-scale observations of grain boundary (GB) dislocation climb in nanostructured Au during in situ straining at room temperature. The climb of a edge dislocation is found to occur by stress-induced reconstruction of two neighboring atomic columns at the edge of an extra half atomic plane in the dislocation core. This is different from the conventional belief of dislocation climb by destruction or construction of a single atomic column at the dislocation core. The atomic route of the dislocation climb we proposed is demonstrated to be energetically favorable by Monte Carlo simulations. Our in situ observations also reveal GB evolution through dislocation climb at room temperature, which suggests a means of controlling microstructures and properties of nanostructured metals. Dislocation climb is crucial to plasticity and creep of materials. Here, the authors report real-time atomic-scale observations of grain boundary dislocation climb in nanostructured Au at room temperature. The dislocation climb occurs by reconstruction of two atomic columns in the dislocation core. [ABSTRACT FROM AUTHOR]

Twin-thickness-controlled plastic deformation mechanisms are well understood for submicron-sized twin-structural polycrystalline metals. However, for twin-structural nanocrystalline metals where both the grain size and twin thickness reach the nanometre scale, how these metals accommodate plastic deformation remains unclear. Here, we report an integrated grain size and twin thickness effect on the deformation mode of twin-structural nanocrystalline platinum. Above a ∼10 nm grain size, there is a critical value of twin thickness at which the full dislocation intersecting with the twin plane switches to a deformation mode that results in a partial dislocation parallel to the twin planes. This critical twin thickness value varies from ∼6 to 10 nm and is grain size-dependent. For grain sizes between ∼10 to 6 nm, only partial dislocation parallel to twin planes is observed. When the grain size falls below 6 nm, the plasticity switches to grain boundary-mediated plasticity, in contrast with previous studies, suggesting that the plasticity in twin-structural nanocrystalline metals is governed by partial dislocation activities. The deformation mechanisms of micron-sized twinned metals are well-understood, but it is not so for twinned nanocrystalline metals. Here, the authors use high resolution microscopy to image the deformation of nanocrystalline twinned platinum and show that grain boundary behaviors dominate plasticity below 6 nm. [ABSTRACT FROM AUTHOR]

Strategies involving metastable phases have been the basis of the design of numerous alloys, yet research on metastable high-entropy alloys is still in its infancy. In dual-phase high-entropy alloys, the combination of local chemical environments and loading-induced crystal structure changes suggests a relationship between deformation mechanisms and chemical atomic distribution, which we examine in here in a Cantor-like Cr20Mn6Fe34Co34Ni6 alloy, comprising both face-centered cubic (fcc) and hexagonal closed packed (hcp) phases. We observe that partial dislocation activities result in stable three-dimensional stacking-fault networks. Additionally, the fraction of the stronger hcp phase progressively increases during plastic deformation by forming at the stacking-fault network boundaries in the fcc phase, serving as the major source of strain hardening. In this context, variations in local chemical composition promote a high density of Lomer-Cottrell locks, which facilitate the construction of the stacking-fault networks to provide nucleation sites for the hcp phase transformation. In dual-phase Cantor-like high entropy alloys, how local chemistry affects enhanced deformation mechanisms remains unclear. Here, the authors image 3D stacking fault networks formation and show they both impede dislocations and facilitate phase transformations via local chemical composition variations. [ABSTRACT FROM AUTHOR]

A detailed in situ investigation of dislocation processes has been rare for nanograined materials with grain sized near or less than 10 nm. Here, we report a time-resolved and atomic-scale in situ transmission electron microscopy observation of the nucleation, motion, annihilation, and storage of full dislocations in nanograins with diameters less than ∼10 nm. Annihilation of dislocation dipoles appears to be a major contributor to the reduction in dislocation density, in addition to annihilation at grain boundary sinks. The accumulation of a high density of dislocations inside nanograins is found to be possible when they are surrounded by neighboring grains. [ABSTRACT FROM AUTHOR]

Nickel-based GH3536 alloy exhibits high strength but low ductility when produced by selective laser melting (SLM), which hinders its widespread application in aerospace. This paper employed a 'two-step' method of heat treatment to optimize the microstructure of the SLM GH3536 alloy and investigated the mechanical properties. Tensile tests were conducted on SLM GH3536 alloy before and after heat treatment at 750 °C, using an in-situ high-temperature tensile stage. The relationship between the microstructural evolution and deformation behavior of the alloys was investigated by combining the in-situ tensile experiments and crystal plasticity finite element method (CPFEM). The results suggested that the elongation can be increased by 80% without a significant reduction in tensile strength. The improved elongation is attributed to the complete recrystallization, formation of annealed twins and serrated grain boundaries after heat treatment. The study also investigated the deformation behavior and fracture mode of the alloy before and after heat treatment. Discussion was done on the influence of the microstructure, particularly the twin and serrated grain boundaries on the alloy's plastic deformation. This study enhanced the understanding of plastic deformation of SLM GH3536 alloy and provided a valuable reference for the design and post-treatment of superalloy. • A two-step heat treatment method is proposed to prepare GH3536 alloy with high ductility and acceptable strength. • High-temperature microplastic deformation and damage of GH3536 alloy were observed in-situ SEM technique and its influencing factors were analyzed. • The effects of twins and serrated grain boundaries on the properties were simulated using the CPFEM model. [ABSTRACT FROM AUTHOR]

Grain boundaries (GBs) in polycrystalline and nanocrystalline materials are rarely flat, and their curvatures often evolve dynamically in three-dimensional (3D) GB network under thermomechanical stimulations. However, the complexity of polycrystalline microstructure greatly hinders our understanding of GB kinetics with 3D crystallographic clarity, especially at atomic scale. Here, we reveal a disconnection-based mechanism of GB kinetics in 3D space, by combining atomic-resolution in situ nanomechanical testing and atomistic simulations. Upon loading, GB can gradually adjust its curvature in 3D via sequential nucleation, propagation and annihilation of curved disconnections, where anisotropic mobilities of different disconnection segments induce a dynamic GB curving in 3D. Such curved disconnection-mediated GB curving and migration can coordinate among multiple GBs, and contribute to 3D grain growth/annihilation in GB networks. This curved disconnection-based 3D GB kinetics elucidates a long-elusive perspective in GB deformation, significantly advancing current knowledge of GB-mediated plasticity in metallic materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: The fretting fatigue tests of steel wires were performed on the self-made fretting fatigue test equipment under different strain ratios ranging from 0.90 to 0.70 with contact loads of 50N and 70N. Curves of Ft–D–N were drawn, and the dissipated energy was calculated through the curves of Ft–D. Morphological features of fretting scar and fracture surface were observed by scanning electron microscopy (SEM). The results reveal that as the strain ratio decreased, the fretting regime changed from partial slip regime to mixed regime and slip regime. Shorter fretting fatigue life, higher wear coefficient were induced by a lower strain ratio. The curves of dissipated energy corresponding to three kinds of fretting regimes were different from each other. Morphologies of adhesive wear, abrasive wear and fatigue wear as well as accumulation of plastic deformation and micro-cracks were observed in fretting scars. All fatigue fractures in different fretting regimes could be divided into three regions. [Copyright &y& Elsevier]

The 3D-printed (TiB + TiC)/Ti6Al4V composite with tailored network reinforcement architecture and heterogeneous α lamellae structure (i.e., a dual-heterogeneous structure) possesses simultaneously improved tensile strength and uniform ductility. To reveal the fundamentals behind the strengthening and deformation mechanisms, the microstructural evolution and tensile deformation behavior of as-printed (TiB + TiC)/Ti6Al4V composite were carefully examined under in-situ tensile testing together with as-printed Ti6Al4V. The heterogeneous structure in the composites induced significant constraint effect, affording deformation compatibility via strain partitioning throughout the composite. Importantly, owing to the heterogeneous α lamellae structure and the pinning effect of reinforcements, the hetero-deformation induced additional strengthening effect and strain-hardening potential, leading to much enhanced plastic deformation capacity and improved strengthening efficiency. Furthermore, the microcracks arresting stabilized the plastic deformation at the later deformation stage and offered extra ductility. Based on these investigations, the intrinsic strengthening and deformation mechanisms behind the synergetic strength-ductility over the whole deformation process were elucidated. This work highlights the importance of heterogeneous structure design strategy in the development of discontinuous metal matrix composites. [Display omitted] • Detailed in-situ SEM tensile tests were conducted to investigate the microstructural evolution and cracking behavior. • The dual-heterogeneous structure greatly affected the tensile deformation and fracture behaviors. • The constraint effect caused by the heterogeneous structure induced strain partitioning. • Pinning effect of reinforcements and interfaces allowed GNDs pile-ups leading to strain hardening. • The diagram of strength-ductility synergy in the whole loading process were elucidated. [ABSTRACT FROM AUTHOR]

Using homemade device, in situ atomic-scale bending experiments were conducted on twinned Ni nanowires. Many in situ atomic-scale observations revealed that the plastic behaviours of twinned Ni nanowires can be significantly affected by the magnitude of the bent strain. In the early stages of bending, their plastic deformation was controlled by dislocations. With increasing bending, fcc-bct phase transitions were observed. When the bent strain increased to a high level, grain boundary resulting from lattice distortion/collapse were detected. This study advances our understanding of the plasticity mechanisms of twinned Ni. Unlabelled Image [ABSTRACT FROM AUTHOR]

Technologically important mechanical properties of engineering materials often degrade at low temperatures. One class of materials that defy this trend are CrCoNi-based medium- and high-entropy alloys, as they display enhanced strength, ductility, and toughness with decreasing temperature. Here we show, using in situ straining in the transmission electron microscope at 93 K (−180 °C) that their exceptional damage tolerance involves a synergy of deformation mechanisms, including twinning, glide of partials and full dislocations, extensive cross-slip, and multiple slip activated by dislocation and grain-boundary interactions. In particular, massive cross-slip occurs at the early stages of plastic deformation, thereby promoting multiple slip and dislocation interactions. These results indicate that the reduced intensity of thermal activation of defects at low temperatures and the required increase of applied stress for continued plastic flow, together with high lattice resistance, play a pivotal role in promoting the concurrent operation of multiple deformation mechanisms, which collectively enable the outstanding mechanical properties of these alloys. [ABSTRACT FROM AUTHOR]

Most mechanisms used for strengthening crystalline materials, e.g. introducing crystalline interfaces, lead to the reduction of ductility. An additive manufacturing process – selective laser melting breaks this trade-off by introducing dislocation network, which produces a stainless steel with both significantly enhanced strength and ductility. Systematic electron microscopy characterization reveals that the pre-existing dislocation network, which maintains its configuration during the entire plastic deformation, is an ideal “modulator” that is able to slow down but not entirely block the dislocation motion. It also promotes the formation of a high density of nano-twins during plastic deformation. This finding paves the way for developing high performance metals by tailoring the microstructure through additive manufacturing processes. [ABSTRACT FROM AUTHOR]

• The process of dislocation slip across grain boundaries activating slip systems within adjacent grains of inconel 718 alloy during the tensile at 650 °C was observed using in-situ SEM technique. • A CPFEM model reflecting the microscopic morphology and lattice orientation of the alloy was developed and its reliability was verified. The evolution process of the slip systems of each grain were simulated using the model. • The slip transfer at general grain boundaries and annealed twin boundaries was investigated using a combination of slip traces analysis method and CPFEM. The influence of slip systems interactions on the slip transfer was analyzed in detail. • 113 results of adjacent grains slip transfer/blocking were counted, and a preliminary criterion for predicting slip transfer of inconel 718 alloy during plastic deformation at 650 °C was established. Adjacent grains slip transfer is an important mechanism for metal adaptation to incompatibilities in intergranular deformation. Thus, this paper investigates slip transmission at grain boundaries (GBs) and annealed twin boundaries (TBs) in Inconel 718 (IN718) alloy using in-situ tensile test at 650 °C by integrating slip trace analysis and the crystal plasticity finite element method (CPFEM). Results show that the m α β criterion, based on the match of intersection lines between slip planes to GB planes and slip directions, is more reasonable in predicting induced activated slip systems than Luster-Morris m α β ′ criterion. In addition, slip transfer tended to occur at m α β ′ > 0.83 and Δ b (1 / b) < 0.44 or m α β > 0.82 and Δ b (1 / b) < 0.46 for general GBs; when m α β ′ > 0.92 or m α β > 0.93 , continuous slip transfer is a crucial mechanism to coordinate strain and reduce stress concentration. Furthermore, the acceptable criteria for slip transfer at TBs are θ ≈ 0 and Δ b (1 / b) < 0.6 by experimental and computational results. This study deepens the understanding of the adjacent grains slip transfer behavior of IN718 and also provides a new strategy to study the deformation behavior of Nickel-based superalloys. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, the plastic behaviors of nanocrystalline Au with an average grain size of 18 nm were investigated in situ using a home-made tensile device in a transmission electron microscope. We provide the direct experimental results revealed the process of grain boundary migration. The results show that dislocation behaviors are prevalent for large grains. However, for grain sizes below ~ 15 nm, grain boundary migration occurs frequently. The results of our statistical analyses show that grain boundary migration occurs more frequently than grain boundary sliding and rotation in nanocrystalline Au. [ABSTRACT FROM AUTHOR]

The effects of grain size on tensile behavior of Inconel718 superalloy have been characterized by an in-situ tensile stage inside a scanning electron microscopy (SEM) combined with electron backscatter diffraction (EBSD) and digital image correlation (DIC) at room temperature. The microstructure evolution and mechanical properties of specimens under different heat treatments were performed and compared. The in-situ tensile test showed that the yield strength, ultimate tensile strength and reduction of cross section decrease with the increasing grain size. An in-situ EBSD study showed that with increasing stress the local plastic deformation become more inhomogeneous. An analysis combined in-situ SEM morphology evolution, DIC strain distribution and EBSD results indicated that the grains deformed coordinately. Geometrically necessary dislocation (GND) density depends on the grain size and the orientation of individual grains. The coordinated deformation ability decreased with increasing grain size. The fracture morphology showed that with the increase of grain size, the fracture mechanism transformed from the ductile transgranular fracture to the brittle intergranular-transgranular mixed fracture. • The mechanical properties and morphology evolution of Inconel718 was investigated by in-situ SEM tensile technology. • The strain distribution evolution were determined combining with digital image correlation (DIC) technique. • The microstructure evolution were determined combining with EBSD technique. • The mechanisms of coordinated deformation and grain size effects were discussed. [ABSTRACT FROM AUTHOR]

Understanding the deformation behavior of crack tips in metals is of great significance for improving fracture toughness. However, how crack tips in nanosized metallic alloys behave under loading is unclear, because most previous studies focused on pure metals. In this study, the atomic-scale deformation behavior of the crack tip in AuAg alloy nanocrystals was observed in situ. We revealed that the deformation mechanism near the crack tip depended on the distance from the tip. For the 'near region' close to the crack tip, plastic deformation was governed by partial dislocations, twinning, and their interactions. For the 'far region', further than ∼15 nm from the crack tip, full dislocations dominated, and their interactions resulted in Lomer-dislocation (LD) lock formation and destruction. We uncovered that the combination of blunting dislocation-twin interactions, twin-twin intersections, and formation and destruction of LD locks, as a previously unrecognized fracture toughness improvement mechanism in metals. [Display omitted] • The atomic-scale deformation behavior of crack tip in AuAg alloy nanocrystals was studied in situ. • The dislocation-twin interactions, twin-twin intersections, and formation and destruction of LD locks were observed. • The deformation mechanism near the crack tip depended on the distance from the tip. [ABSTRACT FROM AUTHOR]

The deformation behavior in polycrystalline Laser melting deposited (LMD) TA15 alloy was investigated at a temperature of 500°C using advanced in-situ Secondary electron microscopy (SEM) tensile setup coupled with Electron backscatter diffraction (EBSD). The grains morphology, crystal orientation, preferred pole texture, activated slip traces, grain boundaries evolution, and strain-induced misorientation were systematically analyzed during tensile straining. It was determined that the diverse α-grains (crystal orientation and morphology) revealed inhomogeneous deformation under tensile loading. The overall strain was allocated by grain rotation and substructure formation. The preferred oriented (0001) pole texture maximum was increased during initial strain level. In contrast, at higher strain, the texture intensity was decreased due to the formation and relocation of the newly formed substructures. The fraction of low angle grain boundaries (LAGBs 2–10°) was increased continually with increasing strain. Strain-induced dislocations within larger grains formed new LAGBs, and the increasing fraction of LAGBs was validated by Kernel average misorientation (KAM) map. The prismatic slip mode was identified as the primary active slip system at the initial deformation stage. The fraction of basal and pyramidal slips increased as the strain increased, describing the opposite trend to prismatic slip. The grains rotation and strain accumulation at the grain boundaries accommodated the plastic deformation, ultimately causing boundary sliding. • In-situ EBSD reveals real time microstructure evolution during tensile deformation. • Laser deposited TA15 demonstrate inhomogeneous deformation under tensile stress. • Basal slip system activates at higher SF values throughout the deformation process. • Large size grains endure subdivision under stress to accumulate the tensile strain. [ABSTRACT FROM AUTHOR]

The plastic deformation behavior of three various orientation specimens of a nickel-based single-crystal (SX) superalloy were investigated by in-situ electron back-scattered diffraction (EBSD) at room temperature. Tensile properties, slip morphology, the evolution of Schmid factor, lattice rotation, and local strain were thoroughly discussed. In [1 1 13] specimen, the interaction of multi slip behavior induced local strain concentration, which restricted the plasticity but enhanced the strain hardening. Due to the single slip behavior, lower tensile strength and higher elongation were discovered in [9 1 7] and [2 1 3] specimens. Furthermore, during the plastic deformation of [1 1 13] specimen, lattice rotation is confined around [0 0 1] pole and shows a dispersive distribution, which is triggered by the multi slip behavior. A modified Sachs model considering multi slip behavior has been developed to predict the lattice rotation, this model is also applicable to severely deformed grains in polycrystalline materials. [ABSTRACT FROM AUTHOR]

In situ tensile tests of Cu single crystalline nanowiresin a high-resolutiontransmission electron microscope reveal a novel effect of sample dimensionson plasticity mechanisms. When the single crystalline nanowire sizewas reduced to <∼150 nm, the normal full dislocation slipwas taken over by partial dislocation mediated plasticity (PDMP).For the first time, we demonstrate this transition in a quantitativemanner by assessing the relative contributions to plastic strain fromPDMP and full dislocations. The crossover sample size is consistent,well within model predictions. This discovery represents yet another“sample size effect”, beyond other reported influenceof sample dimensions on the mechanical behavior of metals, such asdislocation starvation or source truncation, and the “smalleris stronger” trend. [ABSTRACT FROM AUTHOR]

A high-temperature in-situ tensile stage setup developed by the authors was combined with electron backscatter diffraction (EBSD) to study the microstructural evolution behavior of Ti–6Al–4V alloy produced by laser direct melting deposition (LDMD) at 400 °C. This technique provided direct observation of the microstructure evolution and deformation behavior of materials under dynamic tensile loading at operating temperature. The evolution of grain morphology, misorientation angles of grain boundaries, and Schmid factor (SF) were systematically investigated. The results indicated that the grains no longer sustained the initial lamellar morphology and underwent a severe microstructural evolution during plastic deformation. Various grain morphologies were observed at different tensile strain levels. The statistical analysis revealed the reduction of high-angle grain boundaries' (HAGBs) fraction among α/α grains, with the opposite trend for low-angle grain boundaries (LAGBs). The increased Schmid factor values (SF > 0.4) were observed for prismatic (1–100) <11–20> and pyramidal (1–101) <11–20> slip systems, while those of the basal (0001) <11–20> slip system exhibited a sharp drop to SF > 0.4 at higher strain levels. Moreover, it was observed that high-SF grains changed their orientations, while low-SF ones split into smaller grains under tensile load. The kernel average misorientation (KAM) maps showed that deformation promoted dislocation motion, generating many LAGBs. The increasing number of LAGBs and slip openings reduced the boundary resistance and provided an easy path to detour the main crack propagation in response to the applied stress, while the LDMD Ti–6Al–4V specimen showed ductile fracture behavior. [Display omitted] • Microstructural evolution of LDMD Ti-6Al-4V alloy was investigated at 400 °C by in-situ EBSD. • Grain morphology and grain boundary characteristics were analyzed. • Plastic deformation behavior during continuous tensile process was studied. [ABSTRACT FROM AUTHOR]

In this paper, the mechanical behavior of Al, Ni, Cu, Au and Ag nanowires (NWs) with a coherent twin boundary parallel to their longitudinal axis was investigated using molecular dynamics simulation. Our results show that the twin-structure NWs with circular cross-section exhibited a strong twin thickness strengthening effect, which led to their yield stress continuing to increase as the twin thickness decreased. The plastic deformation mechanisms of these NWs were significantly affected by both γ sf /γ usf [the ratio between the stacking fault energy (γ sf) and the unstable stacking fault energy (γ usf)] and the twin thickness. As the twin thickness decreased to three atomic layers, we discovered two new deformation models in the NWs. For Al and Ni, their plasticity was accommodated by lattice distortion resulting in brittle-like necking. Meanwhile, for Cu, Au and Ag, their plasticity was accommodated by lattice distortion and rearrangement that led to new grain formation in the NWs. [ABSTRACT FROM AUTHOR]