Macrostructure Properties Research Articles

A Novel Friction Stir Deposition Technique to Refill Keyhole of Friction Stir Spot Welded AA6082-T6 Dissimilar Joints of Different Sheet Thicknesses.

Joining dissimilar sheet thicknesses of AA6082-T6 alloys by friction stir spot welding (FSSW) provides many advantages in automotive and aerospace applications. The formed keyhole at the end of the FSSW process is one of the typical features after the welding process, which owns the same size as the rotating pin that remains at the joint center. This keyhole destroys the joint continuity and can stimulate serious stress concentration when the FSSW joint bears an external force. To solve this issue, a novel refilling technique was developed for the FSSW keyholes using a friction stir deposition (FSD) technique. The FSSW joints of AA6082-T6 sheets were welded at various rotation speeds from 400 to 1000 rpm and a constant dwell time of 3 s, where a 2 mm sheet thickness was an upper sheet, and a 1 mm sheet thickness was a lower sheet. All the keyhole refilling processes were achieved using a specially designed AA2011-T6 consumable rod to be used for friction stir deposition of continuous layers at a constant deposition parameter of 400 rpm consumable rod rotation speed and a 1 mm/min feed rate. The heat input energy for both the FSSW and refilled FSSW lap joints was calculated. In addition, the FSSW and the FSD temperatures were measured. Macrostructure, microstructure, and mechanical properties in terms of hardness and tensile shear maximum load were evaluated for both the friction stir spot welded (FSSWed) and the refilled FSSW lap joints. The obtained results showed that the keyhole could be successfully refilled with defect-free continuous multilayers after the refill friction stir spot welding (RFSSW) process. All the RFSSW lap joints showed higher tensile shear loads than that given by the FSSW (before refill) lap joints. The RFSSW joint (welded at 600 rpm/3 s and refilled at 400 rpm/1 mm/min) showed a higher tensile shear load of 5400 N ± 100 compared with that recorded by the unrefilled joint (4300 N ± 80). The fracture location and fracture surface of the FSSW and RFSSW were examined and discussed.

Microstructure and mechanical properties of 2195/5A06 dissimilar joints made by resistance spot welding

AA2195-T8 aluminum–lithium (Al Li) and 5A06 Al alloys were joined using resistance spot welding process for the first time. The macrostructure, microstructure, elemental distribution, precipitated phases, microhardness distribution, and tensile shear properties of spot welded joints were investigated. The 2195/5A06 spot welded joints were divided into the fusion zone (FZ), partially melted zone (PMZ), and heat-affected zone (HAZ) based on their microstructure. The FZ was composed of all fine equiaxed spherical grains, which were formed by the heterogeneous nucleation of Zr and Li elements. Elemental distribution results indicated the presence of Cu segregation and the eutectic θ ʹ (Al 2 Cu) phase. Transmission electron microscopy results showed that most precipitates dissolved during welding, and that the FZ contained reduced amounts of δ ′ (Al 3 Li) and β ' (Al 3 Zr) phases. In addition, the FZ exhibited lower microhardness than the base material due to the dissolution of the main strengthening T 1 phases. The tensile shear fracture morphologies of the 2195/5A06 spot welded joints exhibited the characteristics of ductile–brittle hybrid fracture. • The 2195 AlAl Li alloy and 5A06 Al alloy were first joined using resistance spot welding. • Fusion zone of weld nugget was found to be composed of all fine equiaxed spherical grains. • The fracture of 2195/5A06 spot welded joint exhibits a ductile-brittle hybrid fracture.

Microstructural and Mechanical Properties of AZ31B to AA6061 Dissimilar Joints Fabricated by Refill Friction Stir Spot Welding

Dissimilar friction stir spot welds (FSSW) between the magnesium and aluminum alloys are joined, using a novel approach called refill friction stir spot welding. The present work aims to evaluate the macrostructural and mechanical properties of refill friction stir spot welded AZ31B and AA 6061-T6 alloys in two combinations, i.e., identical Mg-to-Mg and dissimilar Mg-to-Al joints, and the results are compared with the results obtained in conventional friction stir spot welding. The hardness profiles of the similar welds had the appearance of a W-shape, and the Thermo mechanically affected zone and heat-affected zone of both methods had lower hardness values than the rest of the weld. Along with the interface between the aluminum and magnesium sheets, a thin intermetallic compound layer of Al12Mg17 has been identified, which has led to an increase in hardness. The static shear strength of both similar and dissimilar refill spot friction welds was much greater than that of traditional spot friction welds. In both similar and dissimilar spot friction welds, two distinct failure scenarios are discovered.

Experimental investigations on mechanical properties of multi-layered structure fabricated by GMAW-based WAAM of SS316L

In the present study, the Gas metal arc welding (GMAW) based Wire-arc additive manufacturing (WAAM) process was used to fabricate a multi-layered structure at optimized process parameters on SS316L using metal wire of SS316L. The multi-layered structure's microstructure, macrostructure, and mechanical properties (tensile test, impact test, microhardness, and fractography) were examined at three locations at the top, middle, and bottom sides of the structure. Macrostructure at different zones has confirmed an appropriate bonding between the two layers, complete fusion without oxidation, and free from defects and unwanted geometries. Microstructure results have observed a colony of columnar dendrites in the bottom zone, coarser grains with vertical growth along with the residual ferrite in the middle zone, and vertical dendritic structure with residual ferrite in skeletal shape in the top zone. Results of all tensile properties for top, middle and bottom zone developed by the WAAM process fall in the range values of wrought SS 316 L. The microhardness values were shown a consistent behavior across the built structure in all three zones. The obtained average value for the impact test has shown better strength than commercially used wrought SS 316 L. The results of fractured tensile and fracture impact test specimens revealed many dimples, which suggests a good ductility of the as-built structure. Thus, the obtained results have shown that the built structure using the GMAW-based WAAM process matches the standards for industrial applications.

Effect of Welding Parameter Conditions of 304L SS and AISI 1015 Dissimilar Steel Weld Joints to Macrostructure and Mechanical Properties

This research is focused on the effect of welding parameter conditions, using Gas Metal Arc Welding, on the macrostructure, mechanical properties, and quality of dissimilar steel weld joints. In this study, the selected joints were low carbon steel (AISI 1015) and austenitic stainless steel (304L SS). The welding current used had three different variations, such as 100, 110, and 120 A. The solid wire electrode used was ER70S6, with a diameter of 1.2 mm. Identification of the macrostructure in the heat-affected zone (HAZ), micro-Vickers hardness, and tensile tests carried out for each GMAW joint specimen. The results were then discussed. The macrostructure of dissimilar steel welded joints at a welding current of 100 A produced a good quality of welded joints and penetration compared to those using welding currents of 110 and 120 A, which had excessive penetration and caused distortion and deformation. The microhardness of the weld metal area was far higher than in other areas. At the current 100 A, the micro-Vickers hardness value of stainless steel 304L SS closing the heat-affected zone (HAZ) had increased from 209 to 226 HV. Likewise, For the welding current of 110 A, the micro-Vickers hardness value rose from 249 to 259 HV, and for the welding current of 120 A, the hardness increased from 225 to 227 HV. In the weld metal area, micro-Vickers hardness for each welding current was 318, 364, and 366 HV, while in the low carbon steel area, the hardness value decreased significantly to 180, 190, and 196 HV. At the current of 100 A, the lowest tensile strength was 359.28 MPa, and yield strength was 303.82 MPa. The tensile strength and yield strength for the current of 110 A were 367.24 MPa and 309.83 MPa, respectively. Meanwhile, at the current of 120A, the tensile strength was at the highest that is 374.86 MPa, and the yield strength value was 315.67 MPa. This study found that the dissimilar steel welded joints experienced an increase in the hardness value of the weld metal, and the tensile test results show that the welded steel joints fractured in the low carbon steel area.

Influence of copper plate positioning, zero tool offset, and bed conditions in friction stir welding of dissimilar Al-Cu alloys with different thicknesses

Friction stir welding of dissimilar thickness aluminum and copper alloys was carried out without offsets by placing the copper at different positions, with horizontal and inclined bed conditions. The influence of the copper plate positions and bed conditions on macro-structure, microstructure, and mechanical properties were investigated. Optical microscopy, FE-SEM, EBSD, Tensile test, bending test, micro-hardness, and XRD analysis were carried out to understand the joint formation mechanism. The joint efficiency of 90% and 80.08% and bending angles of 93˚ and 35˚ were obtained, respectively, when the copper was placed at the middle position with horizontal and inclined bed conditions.

Achievement of defect-free and high-ductility TA5 alloy joint by dynamic supporting friction stir welding

Dynamic supporting friction stir welding (DSFSW) is proposed by developing a novel welding platform. The conventional backing plate is replaced by a small-size supporting column to reduce heat dissipation from weld back in the FSW of titanium alloy. TA5 alloy joints were produced via varied FSW techniques and examinations on macrostructure, microstructure and mechanical properties were carried out. Results reveal that DSFSW enhances material flow by greatly improving the effective heat input into weld, thereby eliminating the flow-related cavity defect. Specifically, DSFSW enables defect-free joint at 250 r/min with a significantly increased welding speed of 55 mm/min (83.3% higher than the conventional FSW). Furthermore, the ductility of joint can be improved more than 20%. Consequently, DSFSW is feasible to obtain high-quality joint of titanium alloy under rather high welding speed.

The Use of Fibreglass Mesh in the Experimental Characterisation of Applied Coating Mortars

Mortars are still among the most used wall coatings, whether lime-based or cement-based or traditional and prepared in situ or pre-dosed. When these mortars are formulated and characterized, the influence of the substrate on their characteristics is not taken into account. To study the influence of the substrate on the mortar characteristics, it is necessary to apply the mortar on the substrate, and after its hardening process, to detach it, test it, and then compare its characteristics with those of standard specimens subjected to standard tests. The central problem focuses on detaching the mortar without damaging it, in order to obtain specimens suitable for testing. For this, a fibreglass mesh, positioned at the mortar–substrate interface, can be used to facilitate the detachment in the experimental program. The objective of the present study is to understand if the fibreglass mesh influences the characteristics of the detached mortar. The methodology adopted was as follows: mortars were applied to the substrates, both using the mesh (with the net positioned at the mortar–substrate interface) and without using the mesh, and after hardening, they were detached and tested; then, the independent sample t-test was used to evaluate the differences between the results obtained for the mortars applied with the mesh and without the mesh. As a result, it was concluded that the use of the mesh does not significantly influence the macrostructural properties studied. The relevance of the present study lies in the development of an experimental methodology that allows for the characterization of mortar’s behaviour after its application on the substrate, i.e., that enables the substrate’s influence to be considered in the formulation of each mortar.

Properties and in vitro digestibility of a bread enriched with lentil flour at different leavening times

The effects of three leavening times (60, 105 and 150 min) on structure and some physico-chemical and nutritional properties of bread added with 20 % of green lentil flour were investigated. Leavening time largely affected bread physico-chemical properties, leading to a significant reduction in moisture content, an increase in weight loss and a darker appearance of bread crumb as leavening time increased. Besides, crumb of bread leavened for the longest time (B150) showed a compact structure and the highest resistance to the compression, while the Young’s modulus increased linearly with the rising of leavening time. By contrast, breads leavened for shorter times (B60 and B105) had a more porous structure with more circular bubbles compared to B150, exhibiting lower deformation resistance. Different bread macrostructure had a significant impact on the in vitro protein and starch digestibility. The α amino nitrogen release and the estimated Glycemic Index (eGI) at the end of digestion reached the lowest values in bread leavened for the longest time (B150). In particular, eGI showed a linear correlation both with the Young’s modulus (R 2 = −0.926) and macrostructural properties (R 2 = 0.902), suggesting that modelling bread structure by acting on leavening time can be a novel approach to develop healthier products. • Leavening time affected structure development of lentil flour (LF) enriched breads. • The glycaemic index was positively correlated to visual porosity of LF bread. • Bread visual porosity was negatively correlated to mechanical properties. • The released amino acids amount after digestion decreased at higher leavening times. • Leavening time could be used to modulate the rate of starch digestion.

Nano-Modified Vibrocentrifuged Concrete with Granulated Blast Slag: The Relationship between Mechanical Properties and Micro-Structural Analysis.

Currently, in civil engineering, the relevant direction is to minimize the cost of the manufacture of the hollow structures of annular sections, as well as their construction and installation efficiency. To optimize the costs associated with building products and structures, it is proposed to apply the technology of vibrocentrifugation, to reconsider and comprehensively approach the raw materials for the manufacture of such products and structures. The purpose of this study is a theoretical substantiation and experimental verification with analytical numerical confirmation of the possibility of creating improved variotropic structures of vibrocentrifuged concrete nano-modified with ground granulated blast-furnace slag. The study used the methods of electron microscopy, laser granulometry, and X-ray diffraction. Slag activation was carried out in a planetary ball mill; samples were prepared on a special installation developed by the authors—a vibrocentrifuge. The optimal and effective prescription–technological factors were experimentally derived and confirmed at the microlevel using structural analysis. The mathematical dependencies among the composition, macrostructure, microstructure, and final properties of vibrocentrifuged concrete nano-modified by slag are determined. Empirical relationships were identified to express the variation of some mechanical parameters and identify the relationship between them and the composition of the mixture. The optimal dosage of slag was determined, which is 40%. Increases in strength indicators ranged from 16% to 27, density—3%.

Improvement of Geo-engineering Properties of Expansive Clayey Soil by using Sodium Chloride and Bagasse Ash

Expansive soils contain minerals such as smectite clays that are capable of absorbing water accompanied by shrink and swell behavior and thus change in volume. The swell–shrink behavior of these soils could lead to instability of the structures found on them, specifically the light-weight structures and pavements. Expansive clay soil is encountered in most parts of Egypt. A comprehensive study was made in Sixth of October city to investigate the impact of lime sludge and bagasse ash as an industrial solid waste from sugar-cane factory and sodium chloride salt on geotechnical engineering properties of expansive soil. The macrostructural properties are quantified through laboratory testing for Free swell index, Plasticity index and infiltration tests. The microstructural aspects of the treated soil are observed through X-ray diffraction studies and SEM micrographs. The laboratory results showed that by increasing the lime sludge, Bagasse ash and NaCl concentrations the liquid limit decreased from 100% to 60% while the plastic limit increased from 100% to 90% respectively. In addition, the infiltration tests showed an increase in the infiltration rate from 10% to 80% when LS and Bagasse ash were added to the soil also the free swell decreased from 100% to 70 % sufficiently. XRD patterns showed the formation of new kaolin cementitious compound as the change of montmorillonite to kaolinite mineral took place due to the reaction of high amount of calcium ions produced from the stabilizer, the cation exchange took place between the calcium cation of the lime associated with the surfaces of the clay particles. The effect of cation exchange and attraction causes clay particles to became close to each other, this process is called flocculation which is accompanied by a series of pozzolanic reactions resulting in the formation of clay aggregates that are bound together by the new cementitious products such as calcium aluminate. Scanning Electron Microscopic images (SEM) and SEM micrographs determined the formation of organized dense clay matrices of aggregations that showed the reduction of Montmorillonite clay mineral peak intensities and an increase in kaolinite clay mineral peak intensities due to the change of expansive soil texture and reduction of interplanar spacing of the treated soil.

Evaluation of nanocomposite structure printed by solid-state additive manufacturing

Properties of polymer-metal hybrid structure printed by fed friction stir additive manufacturing (FFSAM) were evaluated. FFSAM is advanced solid-state additive manufacturing for the printing of macro-scale components for large stress-bearing situations. With the FFSAM, layer by layer printing of polymer and metal sheets convert to paste phase and join together as a uniform structure. With this process, during printing of hybrid structure, nanocomposite polymer is injected at the interface of base materials to fill voids and recover properties of the polymer matrix: polypropylene (PP) and stainless steel (SS) fabric selected as raw materials. During the printing process, Fe2O3 nanoparticles fed into the interface of PP and steel sheets. The mechanical and metallurgical characterization of printed [email protected]@Fe2O3 nanocomposite structure is evaluated. Macrostructure, tensile strength, hardness, and thermo-chemical properties of the printed structure were assessed and discussed. The result indicated that the In-situ feeding mechanism improves the physical and chemical properties of the printed structure. Reasonable properties achieved due to minimizing shrinkage gap in polymer side and improving sealing adhesion at interfaces of printed materials.

Various coagulation techniques and their impacts towards the properties of natural rubber latex from Hevea brasiliensis — a comprehensive review related to tyre application

Coagulation is the first crucial step in the processing of natural rubber (NR) that happens naturally or is induced by various techniques. The mechanism of Hevea latex coagulation involves the destabilization and aggregation of latex particles that are influenced by different factors. By understanding the basics of coagulation process, the use of different coagulation techniques and their efficiency are illustrated in this paper. The corresponding impact on the technological properties of unvulcanized NR is connected to the choice of coagulation technique. For instance, the microstructure of natural coagulated NR relies on the precedence of microbial activities which further decides the mesostructure and macrostructure properties. As NR is widely used in the rubber manufacturing industry notably tyres, the subsequent impacts of coagulated NR using different techniques are described from the aspect of processing, vulcanization characteristics, mechanical properties, and ageing retention properties of NR vulcanizate. By providing such an overview, the connection of coagulation technique of Hevea latex to the rubber industries is established to have a more comprehensive understanding when selecting the best option for the respective application.

A structural study of the self-association of different starches in presence of bacterial cellulose fibrils

A multi-analytical study was performed to analyse the effect of bacterial cellulose (BCF) on the self-association of starches with different amylose content (wheat, waxy-maize), assessing macrostructural properties (rheology, gel strength) and some nano and sub-nano level features (small and wide-angle X-ray scattering). Although pasting viscosities and G′ were significantly increased by BCF in both starches, cellulose did not seem to promote the self-association of amylose in short-range retrogradation. A less elastic structure was reflected by a 2–3-fold increase in loss factor (G″/G′) at the highest BCF concentration tested. This behavior agreed with the nano and sub-nano characterisation of the samples, which showed loss of starch lamellarity and incomplete full recovery of an ordered structure after storage at 4 °C for 24 h. The gel strength data could be explained by the contribution of BCF to the mechanical response of the sample. The information gained in this work is relevant for tuning the structure of tailored starch-cellulose composites.

Microstructure and Mechanical Properties of Dissimilar Friction Stir Welded Joint AA7020/AA5083 with Different Joining Parameters.

The present paper aims to analyze the influence of process parameters (tool traverse speed and tool rotational speed) on the macrostructure, microhardness, and mechanical properties of dissimilar friction stir welded (FSW) butt joints. Nine combinations of FSW parameters welded joints of aluminum alloys 7020-T651 and 5083-H111 were characterized. Plates in 5 mm thickness were welded using the FSW method as dissimilar joints with three values of tool rotation parameters (400, 800, and 1200 rpm) and three welding speeds (100, 200, 300 mm/min). The macroscopic observations revealed various shapes of the stir zone and defects resulting from excess and insufficient heat input. Microfractographic analysis and tensile test results showed that the samples made with the FSW parameters of 800 rpm and 200 mm/min had the best strength properties: UTS = 303 MPa, YS = 157 MPa, and A = 11.6 %. Moreover, for all welds at welding speed 100 mm/min, the joint efficiency reached 95%.

Short-Range Structural Connections Are More Severely Damaged in Early-Stage MS.

Long-range connections are more severely damaged and relevant for cognition in long-standing MS. However, the evolution of such coordinated network damage in patients with MS is unclear. We investigated whether short- and long-range structural connections sustained equal damage in early-stage MS. Sixteen patients with early-stage MS and 17 healthy controls were scanned by high-resolution, multishell diffusion imaging on 7T MR imaging and assessed cognitively. We investigated macrostructural properties in short- and long-range fibers and of microstructural metrics derived from 2 quantitative diffusion MR imaging models: DTI and neurite orientation dispersion and density imaging. Patients had significant WM integrity damage-that is, higher radial diffusivity and a lower intracellular volume fraction in the focal WM lesions. Compared with the healthy controls, the patients had noticeable microstructure changes in both short- and long-range fibers, including increased radial diffusivity, mean diffusivity, and axial diffusivity. Z scores further indicated greater damage in the short-range fibers than in the long-range fibers. Our findings demonstrate that more severe demyelination preceding axonal degeneration occurs in short-range connections but not in long-range connections in early-stage MS, suggesting the possibility that there are cortical lesions that are undetectable by current MR imaging.

Mechanical and macrostructural properties of 3D printed concrete dosed with steel fibers under different loading direction

Currently, the 3D manufacturing of cementitious materials is at the preliminary stage. The utilization of the various materials and the anisotropic behavior of 3D printed mix is still an uncharted section. This study investigates the significance of loading orientation on 3D printed concrete infilled with steel fibers. The fresh characteristics and compressive strength were tested using conventional techniques under different loading directions (0°, 45° and 90°). Whereas porosity, fractal characteristics and failure planes of the 3D printed concrete were characterized using X-Ray computed tomography (X-CT). The fractal characteristics and porosity showed a strong correlation between each other. Moreover, the tradeoffs between the layer orientation and loading planes directly reduce the compressive strength. The mix with 0.75% of steel fibers showed the highest compressive strength at an angle of 90° to the loading direction. No interlayer pores were observed in the X-CT scan because of the better quality and compaction of the 3D printed concrete.

Micro and macro-structural properties of waste tyre rubber fibre-reinforced bacterial self-healing mortar

Incorporating waste originated fibre in cementitious mixes facilitate safe waste disposal and leads to environment-friendly construction practices. The use of waste originated fibre sometimes degrades cementitious mixes’ properties due to weak fundamental properties of waste originated fibre. In the present study, waste tyre rubber (WTR) fibre was used to prepare fibre-reinforced self-compacting mortar (SCM) up to 2% volume fraction. To improve the efficacy of WTR fibre-reinforced SCM, calcite precipitating bacteria Escherichia Coli was introduced to the mix by i) direct addition with the mixing water and ii) the use of WTR fibre as bacteria carrier. The effectiveness of two different modes of the bacteria incorporation was evaluated by performing the air content, density, flow spread, and flow time test as fresh state properties. The microstructural characterisation, self-healing ability, compressive strength, flexural strength, indirect tensile strength, porosity, and water absorption tests were conducted as hardened state properties. Results indicated that untreated WTR fibre improved the flow of SCM, whereas bacteria immobilised fibre hindered particle movements of the fresh SCM. Microstructural characterisation revealed loose and non-uniform bacterial calcite precipitation over untreated WTR fibre while incorporating WTR fibre as bacteria carrier showed properly adhered calcite precipitation. Compared to the untreated WTR fiber-reinforced SCM, bacteria immobilised WTR fiber-reinforced SCM exhibited the highest mechanical and durability properties. This study compares two modes of incorporating the bacteria, which indicated that the use of WTR fibre as a bacteria carrier improved the properties of fibre-reinforced SCM.

Microstructural Patterns, Microsegregation, Porosity, and Mechanical Properties of Hypoeutectic Al-Fe Alloy, and its Dependency with Solidification Thermal Parameters

Al-Fe alloys are usually used as packaging and structural materials, but in the recent years, there have been considered for possible applications in aerospace field. The solidification sequence in pure aluminum containing 1 wt.% Fe is described in term of the formation of macrostructure, microstructure, microsegregation, porosity and mechanical properties. This material was studied in the upward unidirectional solidification system under transient heat flow conditions. Differences in microstructure, microsegregation, porosity and mechanical properties such as ultimate tensile strength, elongation and microhardness, due to the thermal parameter effects were observed and discussed. Experimental growth laws relating cellular spacing to the cooling rate and solidification speed have been determined, indicating that the increase in thermal parameter have induced a refinement effect on cell morphology. Microsegregation profiles of Fe solute were experimentally determined from the central region of the cell to the intercellular region under different solidification speeds. The Fe microsegregation determined from central region of the cell (FS = 0) to the intercellular region (FS = 1) show a growing profile, in any case considered. However, the profiles move upward with the increase in solidification speed, which indicates that Fe solubility in solid, increases with the increase in solidification speed. The effect of the solidification thermal parameters and cellular spacing on the porosity content were experimentally investigated. The value of porosity content increased along the casting. These results have pointed out that porosity content is affected by solidification parameters and cellular patterns. Further, measurable effects of the thermal parameters, cellular spacing and porosity content on the mechanical properties were experimentally determined. It stands out among experimental results the influence of porosity on the mechanical properties of as-cast material. In any case analyzed, mechanical properties increase with decreasing porosity content.

Structural brain connectivity in children after neonatal stroke: A whole-brain fixel-based analysis

IntroductionNeonatal arterial ischemic stroke (NAIS) has been shown to affect white matter (WM) microstructure beyond the lesion. Here, we employed fixel-based analysis, a technique which allows to model and interpret WM alterations in complex arrangements such as crossing fibers, to further characterize the long-term effects of NAIS on the entire WM outside the primary infarct area. Materials and methods32 children (mean age 7.3 years (SD 0.4), 19 male) with middle cerebral artery NAIS (18 left hemisphere, 14 right hemisphere) and 31 healthy controls (mean age 7.7 years (SD 0.6), 16 male) underwent diffusion MRI scans and clinical examination for manual dexterity. Microstructural and macrostructural properties of the WM were investigated in a fixel-based whole-brain analysis, which allows to detect fiber-specific effects. Additionally, tract-averaged fixel metrics in interhemispheric tracts, and their correlation with manual dexterity, were examined. ResultsSignificantly reduced microstructural properties were identified, located within the parietal and temporal WM of the affected hemisphere, as well as within their interhemispheric connecting tracts. Tract-averaged fixel metrics showed moderate, significant correlation with manual dexterity of the affected hand. No increased fixel metrics or contralesional alterations were observed. DiscussionOur results show that NAIS leads to long-term alterations in WM microstructure distant from the lesion site, both within the parietal and temporal lobes as well as in their interhemispheric connections. The functional significance of these findings is demonstrated by the correlations with manual dexterity. The localization of alterations in structures highly connected to the lesioned areas shift our perception of NAIS from a focal towards a developmental network injury.