Strong Deformation Research Articles

Giant Piezoelectricity of Deformed Aluminum Nitride Stabilized through Noble Gas Interstitials for Energy Efficient Resonators

AbstractAluminum nitride (AlN) is a material for a wide range of microwave‐frequency electronics devices, because of its piezoelectric properties and high chemical stability. To improve the performance of AlN‐based devices, such as acoustic wave filters and energy harvesters, an increased piezoelectric modulus is desirable. Here, an increase of the piezoelectric modulus d33 of this material is achieved by ion implantation of noble gases. For a fluence of 3 × 1016 at cm−2 Ar+, a 30% increase of d33 of AlN is obtained. The improvement is attributed to noble gas atoms implanted into interstitial sites of the wurtzite structure, causing a strong deformation of wurtzite AlN. Density functional theory calculations reveal the formation of deformed, metastable AlN with a 350% increase of the longitudinal piezoelectric coefficient. The ion implantation conditions to prepare AlN with a high piezoelectric coefficient are discussed and verified by X‐ray diffraction, Raman spectroscopy, and scanning transmission electron microscopy. Heavier elements, larger fluences, and an implantation angle not aligned to the wurtzite crystal are preferred since those conditions generate tetrahedrally coordinated interstitials. In contrast, the opposite conditions lead to octahedrally coordinated interstitials prior to relaxation, which activates the silent B1high phonon vibration and results in a reduced piezoelectric coefficient.

Texture Evolution and Control of 2524 Aluminum Alloy and Its Effect on Fatigue Crack Propagation Behavior

The influences of cold rolling and subsequent heat treatment on the microstructure evolution of 2524 alloy were investigated using an orientation distribution function (ODF) and electron back-scattered diffraction (EBSD). A preparation method of 2524-T3 aluminum alloy with a strong Brass texture was developed, and its effect on the fatigue properties of the alloy was investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that with the increase in cold rolling deformation from 0% to 80%, the volume fractions of Brass, copper, and S textures in the 2524-T3 alloy also increase, especially in the case of Brass and S textures. However, the volume fractions of cube and Goss textures are reduced significantly, especially for cube textures, which are decreased by 57.4%. Reducing coarse second-phase particles (CSPs) is conducive to the formation of a strong deformation texture during cold rolling. A 10% deformation at each rolling pass, followed by a step annealing, helps the preservation of a Brass texture even after solution treatment at 500 °C for 0.5 h, while a large cold deformation followed by high-temperature annealing helps the formation of a strong cube texture. The Brass texture can enhance the strength while decreasing the fatigue crack growth resistance of this alloy.

Evidence of crustal disequilibrium melting, mingling processes, layering and deformation in UHT conditions: The marginal zone of the Egersund-Ogna massif-type anorthosite (S. Norway)

Septa of banded gneisses crop out along the margin of the Proterozoic Sveconorwegian Egersund-Ogna (EGOG) anorthosite pluton. They permit the observation of the effects of a diapiric intrusion of anorthosite on its envelope of gneisses. The rocks are mylonitic and result from a strong deformation in UHT granulite facies conditions due to contact metamorphism. Concordance of the foliations in the septa and in the leuconoritic margin of the anorthosite suggests that the deformation was linked to the ballooning of the anorthosite. The septa lithology is dominated by noritic gneisses interleaved with felsic gneisses and comprises minor amounts of mafic granofels, metaquartzites and metagreywackes. A charnockitic dyke is cutting across the foliated structure. Geochemical data (major and trace elements) indicate that the noritic gneisses did not result from the metamorphism of amphibolites belonging to the high-grade gneiss complex characteristic of the wall rocks of the Rogaland anorthosite province. Instead they have strong similarities with a high-alumina basalt that is the possible parental magma of the EGOG anorthosite. Slight variations from norite to leuconorite compositions were induced by metamorphic differentiation. The felsic rocks encompass a large interval of rock types from granite to tonalite and quartz diorite. They compare with leucogranitic enclaves occurring in the charnockitic upper part of the Bjerkreim-Sokndal layered intrusion. Most felsic lithologies show the signature (including high positive Eu anomalies) of anatectic processes in disequilibrium melting conditions and rapid extraction from the source rocks. Flowage differentiation in the emplacement process explains the various compositions, as commonly observed in migmatite leucosomes. The metaquartzites show a relatively high Ti concentration and the Ti-in-quartz geothermometer records a minimum temperature of 820 °C. The study brings evidence that the high-alumina basalt and the felsic magmas were aggregated but did not interacted to yield hybrid magmas, possibly because the time interval was too short. They mingled in various proportions to form the norito-felsic gneisses. The aggregated magmas were intimately linked to the EGOG intrusion in which they played a role as a lubricating agent. They were injected into the wall rocks and were deformed by ballooning from superheated UHT conditions down to subsolidus conditions where mylonitic structures developed. Finally, a charnockitic magma was still able to intrude at a lower temperature below the ductile-brittle transition.

Structural and electronic properties of N-doping ultra-small diameter (3,3) armchair SWCNT by using PBE and TB-mBJ potentials

The structural and electronic properties of (3,3) ultra-small SWCNT doped with nitrogen at different sites namely N(3,3)_1, N(3,3)_2 and N(3,3)_3 are investigated by DFT method. The first model represents (3,3) small carbon-nitride nanotube (CNNT), the second and third models, three and two linear chains of N atoms replace a linear chain of C atoms in (3,3) SWCNT along the axis of nanotube. Our results show these last two models induce a strong structural deformation of the SWCNT by adopting a cross section in the form of a triangle-like and an ellipse-like respectively and all structures are energetically stable. The electronic properties (band structure, bandgap, total and partial density of states) were determined by using PBE and (TB-mBJ) potentials. After N-doping, the (3,3) SWCNT transforms from semiconductor to metal in CNNT. However, it keeps the same semiconductor behavior in the third model with increase in the bandgap. In N(3,3)_2 model, the gap closes at two Weyl nodes which shows that this configuration is in Weyl semi-metal (WSM) state due to the break in symmetry. Furthermore, we observe that all DOS curves were changed a lot after doping and that the impurities levels appear clearly. Our results open new possibilities for developing electronic nanodevices of extremely small size and opens the field for experimental study of the new topological materials based on CNT doped with nitrogen.

Research and Analysis of Civil Airport Asphalt Concrete Pavement Damage Cause Evaluation and Countermeasure

Asphalt concrete pavement is characterized by convenient construction and maintenance, ride comfort, low noise, and strong adaptation and coordination deformation. Therefore, it has been gradually used in civil aviation transport airport runway, especially in recent years, the proportion of runways used in large hub airports has increased. However, asphalt concrete pavement also has many issues that is not conducive to the security of airport operation and management under the influence of traffic load, natural environment, and material performance. This paper analyzes and studies the causes and countermeasures of the damages through the investigation of several cases of asphalt concrete pavement damages in China, so as to provide reference for the extensive application and maintenance management of asphalt concrete pavement in airports in the future.

Comment on Strauss et al., 2020: Subsidence analysis of salt tectonics‐driven minibasins (Northern Calcareous Alps, Austria)

Comment on Strauss et al., 2020: Subsidence analysis of salt tectonics‐driven minibasins (Northern Calcareous Alps, Austria)

A non-Archimedean analogue of Teichm\xfcller space and its tropicalization

In this article we use techniques from tropical and logarithmic geometry to construct a non-Archimedean analogue of Teichmüller spaceoverline{{{mathcal {T}}}}_g whose points are pairs consisting of a stable projective curve over a non-Archimedean field and a Teichmüller marking of the topological fundamental group of its Berkovich analytification. This construction is closely related to and inspired by the classical construction of a non-Archimedean Schottky space for Mumford curves by Gerritzen and Herrlich. We argue that the skeleton of non-Archimedean Teichmüller space is precisely the tropical Teichmüller space introduced by Chan–Melo–Viviani as a simplicial completion of Culler–Vogtmann Outer space. As a consequence, Outer space turns out to be a strong deformation retract of the locus of smooth Mumford curves in overline{{mathcal {T}}}_g.

A Lower Devonian age for the Corvock Granite and its significance for the structural history of South Mayo and the Laurentian margin of western Ireland

The Silurian Croagh Patrick succession, which crops out just south of a fundamental Caledonian structural zone near Clew Bay, western Ireland, is a series of psammites and pelites with a strong penetrative cleavage. These rocks are intruded by the Corvock granite. A suite of minor intrusions associated with the granite contains the regional cleavage whereas the Corvock granite is undeformed. New U–Pb dates are 413 +7 / –4 Ma for a strongly cleaved sill and 410 ± 4 Ma for the main granite, and closely constrain the age of crystallization of the granite and coeval cleavage formation as Lower Devonian (Lochkovian or Pragian), implying syn- to late-kinematic granite emplacement. These data are consistent with evidence for strong sinistral shear shown by the Ox Mountains granodiorite just to the northeast dated at 412.3 ± 0.8 Ma. This Devonian cleavage is superimposed on Ordovician rocks of the South Mayo Trough. The localisation of the strong deformation is interpreted as being due to its position at a restraining bend during regional sinistral motion on a segment of the Fair Head – Clew Bay Line to the north. Contemporaneous deformation in the syn-kinematic Donegal batholith suggests a transfer of sinistral motion to this intra-Grampian structure rather than simple along-strike linkage to the Highland Boundary Fault in Scotland. Our new data indicate diachronous deformation during the late Silurian and early Devonian history of the Irish and Scottish Caledonides and also support previous interpretations of diachronous deformation between these areas and the Appalachian orogens.

Silurian stratigraphy and graptolite faunas of the Mora 001 and Solberga 1 drill cores, Siljan District, central Sweden

The Mora 001 and Solberga 1 drill cores provide the best available overview on the early Silurian (Llandovery, Rhuddanian to Telychian) graptolite succession available for the Siljan Ring impact structure of central Sweden. The Solberga 1 succession includes a nearly complete graptolite succession from the Pernerograptus revolutus Biozone (late Rhuddanian) to the Oktavites spiralis Biozone (late Telychian). Older graptolite faunas are unknown from the Siljan region. The Mora 001 drill core includes a graptolitic succession from the Monoclimacis crenulata Biozone to the O. spiralis Biozone, found in two lithostratigraphically separated lithological units here identified as the Kallholn Formation. A slice of the Orsa Sandstone Formation of possible later Silurian age is tectonically introduced into the Kallholn Formation in the Mora 001 drill core. The strong tectonic deformation of the Kallholn Formation in both drill cores can easily be understood through the Devonian impact history of the region.

Impacts of the baking heating rate on the water mobility, starch microstructure and mechanical properties of degassed crumb during staling

In this study, the impacts of different heating rates (HRs) from 6 to 40 °C/min were investigated in terms of the 1H proton water mobility, starch microstructure, texture, soluble amylose (AM), amylopectin (AP) retrogradation and AM crystallization during staling. A degassed breadcrumb baked in a miniaturized baking system was used to ensure better time-temperature control during baking. Proton nuclear magnetic resonance (1H NMR) data showed that the evolution of the proton T2 relaxation time decreased with increasing HR during staling. The amount of soluble AM, AP retrogradation degree, AM crystallization degree and crumb firmness tend to increase at higher HR. Environmental scanning electron microscopy (ESEM) observations showed that most starch granules in crumbs treated at higher HR exhibited strong deformation and disruption. These results confirmed that the increase in crumb firmness during staling with increasing HR was related to a higher level of starch disruption. This yielded a higher degree of separation between the AM and AP, which resulted in more pronounced water trapping in the starch crystals. The resulting dehydration of the matrix (gluten network, with AM gel surrounding of starch granules) yielded a loss in crumb softness, and crumb baked at higher HR tended to have a firmer texture and faster staling.

Long-Term and Emergency Monitoring of Zhongbao Landslide Using Space-Borne and Ground-Based InSAR

This work presents the ideal combination of space-borne and ground-based (GB) Interferometric Synthetic Aperture Radar (InSAR) applications. In the absence of early investigation reporting and specialized monitoring, the Zhongbao landslide unexpectedly occurred on 25 July 2020, forming a barrier lake that caused an emergency. As an emergency measure, the GB-InSAR system was installed 1.8 km opposite the landslide to assess real-time cumulative deformation with a monitoring frequency of 3 min. A zone of strong deformation was detected, with 178 mm deformation accumulated within 15 h, and then a successful emergency warning was issued to evacuate on-site personnel. Post-event InSAR analysis of 19 images acquired by the ESA Sentinel-1 from December 2019 to August 2020 revealed that the landslide started in March 2020. However, the deformation time series obtained from satellite InSAR did not show any signs that the landslide had occurred. The results suggest that satellite InSAR is effective for mapping unstable areas but is not qualified for rapid landslide monitoring and timely warning. The GB-InSAR system performs well in monitoring and providing early warning, even with dense vegetation on the landslide. The results show the shortcomings of satellite InSAR and GB-InSAR and a clearer understanding of the necessity of combining multiple monitoring methods.

Overlapping Additive Schwarz preconditioners for isogeometric collocation discretizations of linear elasticity

Overlapping Additive Schwarz (OAS) preconditioners are here constructed for isogeometric collocation discretizations of the system of linear elasticity in both two and three space dimensions. Isogeometric collocation methods are recent variants of isogeometric analysis based on the numerical approximation of the strong form of partial differential equations at appropriate collocation points. Numerical results in two and three dimensions show that two-level OAS preconditioners are scalable in the number of subdomains N, quasi-optimal with respect to the mesh size h and optimal with respect to the spline polynomial degree p. Moreover, two-level OAS preconditioners are more robust than one-level OAS and non-preconditioned GMRES solvers when the material tends to the incompressible limit, as well as in the presence of strong deformation of the NURBS geometry.

An exploration of microstructural in-homogeneity in the 6082 Al alloy processed through room temperature multi-axial forging

In the current work, open die multi-axial forging (MAF) of 6082 Al alloy was performed at room temperature. The resulting microstructure and mechanical properties were found to have a gradient from the periphery towards the center. The resulting inhomogeneity was quantified with the help of electron backscattered diffraction, X-ray diffraction analysis, hardness and tensile strength measurement. The recrystallized grains were found after the partition of inverse pole figure (IPF) maps by using the criteria (Grain orientation spread<1°& boundary misorientation angle>15°). The sub-grains were found by partition of the IPF-maps by using the criteria (Grain orientation spread>2° & 2° < Grain rotation angle<15°). The high driving force (dislocation density) available at center of the MAF sample was responsible for the increase in sub-grains size up-to micrometer regime as well as increase in the volume fraction of recrystallized grains. The presence of a strong deformation texture (Goss ({110} 〈001〉)) and the recrystallized texture (Rotated Cube texture ({001} 〈110〉)) were observed, as we proceed towards the center of the MAF sample.

Dynamical properties of different models of elastic polymer rings: Confirming the link between deformation and fragility.

We report extensive numerical simulations of different models of 2D polymer rings with internal elasticity. We monitor the dynamical behavior of the rings as a function of the packing fraction to address the effects of particle deformation on the collective response of the system. In particular, we compare three different models: (i) a recently investigated model [N. Gnan and E. Zaccarelli, Nat. Phys. 15, 683 (2019)] where an inner Hertzian field providing the internal elasticity acts on the monomers of the ring, (ii) the same model where the effect of such a field on the center of mass is balanced by opposite forces, and (iii) a semi-flexible model where an angular potential between adjacent monomers induces strong particle deformations. By analyzing the dynamics of the three models, we find that in all cases, there exists a direct link between the system fragility and particle asphericity. Among the three, only the first model displays anomalous dynamics in the form of a super-diffusive behavior of the mean-squared displacement and of a compressed exponential relaxation of the density auto-correlation function. We show that this is due to the combination of internal elasticity and the out-of-equilibrium force self-generated by each ring, both of which are necessary ingredients to induce such a peculiar behavior often observed in experiments of colloidal gels. These findings reinforce the role of particle deformation, connected to internal elasticity, in driving the dynamical response of dense soft particles.

Triple enhancement of quasi-SU(3) quadrupole collectivity in Strontium-Zirconium N ≈ Z isotopes

It is notable that along the N=Z line in the nuclear chart, extremely large collectivity emerges suddenly in the mass-80 region. By applying the Monte Carlo shell model (MCSM) and the Hartree-Fock-Bogolyubov plus generator coordinate method (HFB+gcm), we study this problem to find the origin. On the basis that both calculations reproduce the experimental data of the N≈Z nuclei with A=64∼88, we identify the backbone from full shell-model calculations that can explain the strong prolate deformation. We find that inclusion of the 2d5/2 orbit in the model space to cooperate with 1g9/2 is the key ingredient to describe the rapid increase of collectivity from 70Se to 76Sr and to produce the observed large B(E2) values in 76Sr, 78Sr and 80Zr. The quadrupole-quadrupole (QQ) interaction acting between the quasi-SU(3) partner orbits, 1g9/2−2d5/2, is the driving force that changes the nuclear shape from oblate- to prolate-deformed. We further suggest that the quasi-SU(3) effect is particularly amplified in the N≈Z nuclei because these are the unique examples where quasi-SU(3) partner orbits can be formed, like the nuclear pairing, simultaneously in three different types: neutron-neutron (n-n), proton-proton (p-p), and neutron-proton (n-p), which respectively interact through the n-n, p-p, and n-p components of the QQ force to enhance the quadrupole collectivity coherently.

S wave Velocity Structure of the Crust and Upper Mantle Beneath Shanxi Rift, Central North China Craton and its Tectonic Implications

AbstractThe Shanxi rift is located in the central part of the North China Craton (NCC). With strong tectonic deformation and intense seismic activity, its crust‐mantle deformation and deep structure have always attracted wide attention. Using teleseismic events observed in a dense network of 610 temporary and 127 permanent stations in the central NCC, we obtained the crust‐mantle S wave velocity structures by the joint inversion method of receiver functions and surface wave dispersion data. Our results show that the crust thickens in the northern part of the Shanxi rift (41 km) and thins in the southern part (35 km). The Taiyuan and Linfen basins, located in the central part, have high‐velocity zones in the lower crust and upper mantle; beneath the Yuncheng basin in the south, there are low‐velocity zones in the lower crust and uppermost mantle (30–80 km); the Datong basin, located in the northern part of the rift, exhibits a wide range of low‐velocity anomalies in the middle to lower crust and upper mantle. We speculate that the destruction of the NCC and associated lithospheric thinning had a significant impact on the southern part of the rift, but is still in its early stage in the central part, which retains most of the craton features. An upwelling of the asthenospheric magma occurred beneath the western part of the Datong basin. The horizontal deflection of the asthenospheric flow causes low‐velocity anomalies in its surrounding area, which is consistent with LAB topography.

Intensity Change of Binary Tropical Cyclones (TCs) in Idealized Numerical Simulations: Two Initially Identical Mature TCs

AbstractThis study investigates the intensity change of binary tropical cyclones (TCs) in idealized cloud-resolving simulations. Four simulations of binary interaction between two initially identical mature TCs of about 70 m s−1 with initial separation distance varying from 480 to 840 km are conducted in a quiescent f-plane environment. Results show that two identical TCs finally merge if their initial separation distance is within 600 km. The binary TCs presents two weakening stages (stages 1 and 3) with a quasi-steady evolution (stage 2) in between. Such intensity change of one TC is correlated with the upper-layer vertical wind shear (VWS) associated with the upper-level anticyclone (ULA) of the other TC. The potential temperature budget shows that eddy radial advection of potential temperature induced by large upper-layer VWS contributes to the weakening of the upper-level warm core and thereby the weakening of binary TCs in stage 1. In stage 2, the upper-layer VWS first weakens and then restrengthens with relatively weak magnitude, leading to a quasi-steady intensity evolution. In stage 3, due to the increasing upper-layer VWS, the nonmerging binary TCs weaken again until their separation distance exceeds the local Rossby radius of deformation of the ULA (about 1600 km), which can serve as a dynamical critical distance within which direct interaction can occur between two TCs. In the merging cases, the binary TCs weaken prior to merging because highly asymmetric structure develops as a result of strong horizontal deformation of the inner core. However, the merged system intensifies shortly after merging.

Strong work hardening in a high niobium-containing TiNi-based bulk glassy alloy composite

In this study, a high niobium-containing bulk glassy alloy composite Ti41Ni39Nb17.5Al2.5 consisting of amorphous, B2-TiNi and β-Nb phases was fabricated through in situ precipitation strategy by utilizing copper-mold suction casting. Upon compressive loading, the composite alloy showed a pronounced average plastic strain of (17.6 ± 3.5)% and a high fracture strength of (2279 ± 33) MPa together with a strong work-hardening deformation behavior. The volume fraction of the amorphous phase in the composite was determined to be around 23 vol%. The work softening caused by the formation of shear bands can be compensated by the work hardening arising from the pile-ups of dislocation and severe lattice distortion in the precipitated crystals and thereby stabilize the plastic deformation of the composite material. The findings imply that the room-temperature mechanical properties of bulk glassy alloy composites can be well tailored by selecting suitable reinforcers.

Bow shock transients caused by solar wind dynamic pressure depletions

The bow shock and the dayside magnetopause are the principle boundaries that determine the interaction of the magnetosphere with the solar wind. Specifically, the bow shock determines the properties of the shocked solar wind plasma that interacts with the magnetosphere. In addition to the shocked solar wind plasma, a number of transient events associated with the bow shock and foreshock regions can have a major impact on the magnetosphere. Among these transients, specifically so-called hot flow anomalies (HFAs) can play a significant role for magnetospheric physics including auroral and ionospheric perturbations, ultra low frequency waves, and strong deformations of the magnetospheric boundaries. This paper first reviews the properties and types of bow shock transients with a focus on HFAs, and than investigates the response of oblique fast shocks with upstream transient density depleted regions. It is demonstrated that a density depleted flux tube can cause all of the typical properties associated with HFAs. The results are discussed in the context of observations and simulation.

In situ X-ray tomography characterisation of 3D deformation of C/C-SiC composites loaded under tension

C/C-SiC composites fabricated through Liquid Silicon Infiltration were tested under monotonic tension with in situ X-ray computed tomography. The specimens had different fibre orientations with respect to the tensile direction, 0°/90° and ±45°, such that the tension accounted for in-axis and off-axis loads, respectively. The 3D XCT images provided explicit visualisations and quantitative measurements of the distributions of SiC-Si and the orientations of the C fibre bundles. The full-field displacement and strain fields were measured by Digital Volume Correlation, observing a difference in the local deformations in response to the in-axis and off-axis loading. In both specimens, the tensile load triggered significant strain localisations at low stress (<50 MPa). Strong local deformations, observed at both low and high applied stresses, were mostly in the through-thickness direction, indicating local delamination. These observations show the importance of residual stresses to damage development in C/C-SiC composites.