Search Results (5,213)

Carbon fibre-reinforced polymer (CFRP) composites represent promising lightweight materials for automotive powertrain systems, where increasing demands for weight reduction, energy efficiency, and emission reduction are driving the replacement of conventional metallic components. However, automotive powertrain environments expose CFRP materials to elevated temperatures, cyclic mechanical loading, chemical exposure, and tribological interactions, creating complex degradation conditions that significantly influence long-term durability and reliability. This review systematically analyzes CFRP composites for automotive powertrain applications, focusing on the relationship between operational requirements, material selection, reinforcement architecture, manufacturing technologies, and degradation mechanisms. High-performance thermoplastic systems such as CF/PEEK, CF/PPS, and CF/PEKK are critically compared with conventional thermoset composites. CF/PEEK systems demonstrate superior thermomechanical stability, maintaining significant mechanical performance at temperatures approaching 250 °C and tensile strengths of approximately 1400–1600 MPa, whereas CF/PPS composites provide a more economically efficient compromise between thermal resistance, chemical stability, manufacturability, and recyclability for medium-temperature applications. The review further analyzes dominant degradation mechanisms, including creep deformation, fatigue damage, delamination, fibre–matrix interface degradation, and tribological wear. CFRP degradation is shown to result from the interaction of multiple coupled mechanisms rather than from isolated material failure modes. Tribological wear rates typically range from 10⁻⁶ to 10⁻⁵ mm³/(N·m), while creep–fatigue interactions may reduce component lifetime by up to 40–60% under combined thermomechanical loading. Advanced design strategies, including fibre orientation optimization, laminate architecture tailoring, thickness gradation, and hybrid metal–composite structures, are evaluated together with major manufacturing technologies such as injection moulding, compression moulding, overmoulding, automated fibre placement, and additive manufacturing. The presented review establishes an integrated framework linking material systems, operating conditions, manufacturing processes, and durability requirements for automotive powertrain applications. The analysis demonstrates that no universal CFRP system exists for all powertrain components and that optimal material selection requires balancing thermal stability, fatigue resistance, tribological performance, manufacturability, recyclability, and economic constraints according to the specific operating conditions of each component category. Full article

To improve the surface properties of Q235 steel, two types of composite coatings were prepared using laser cladding technology: a 25% WC + 75% Ni60 coating (Group NO) and a 25% WC + 73% Ni60 coating with 2% ZrO₂ added (Group 2). Through XRD, SEM, microhardness testing, friction and wear testing, and electrochemical testing, the effects of ZrO₂ on the phase composition, microstructure, mechanical properties, and corrosion resistance of the coatings were systematically investigated. The results indicate that upon the addition of ZrO₂, Zr atoms solid-solve into the γ-Ni lattice, causing the grain size to refine from 17.36 nm to 10.84 nm, and the carbides to transform from coarse cuboidal particles (average 4.00 μm) into fine, irregularly shaped, dispersed particles (average 2.93 μm); the average hardness of the coating decreased from 901.51 HV0.2 to 576.20 HV0.2, but the uniformity of the hardness distribution improved significantly (standard deviation decreased from 142.75 to 29.74); the coefficient of friction increased from 0.71 to 0.85, and the wear volume increased from 0.04 mm³ to 0.38 mm³, indicating a decline in wear resistance; in a 3.5% NaCl solution, the corrosion potential shifted positively by 38 mV, and the corrosion rate decreased from 0.7234 mm·a⁻¹ to 0.7071 mm·a⁻¹, indicating a slight improvement in corrosion resistance. In summary, the addition of 2% ZrO₂ achieves grain refinement, carbide homogenization, and improved corrosion resistance, but reduces hardness and wear resistance. It is suitable for operating conditions where corrosion resistance and microstructural uniformity are the primary considerations. Full article

Tribological systems involving rolling and sliding contacts generate coupled mechanical interactions that govern friction, wear, and surface degradation. These interactions produce multiaxial residual stresses that influence crack initiation, accelerate wear, and promote environmentally assisted damage. In corrosive environments, tribo-corrosion further intensifies material degradation through the combined action of mechanical wear and electrochemical reactions. Protective organic and metallic coatings are widely used to mitigate these effects; however, their performance depends on adhesion, stress evolution, and resistance to coupled mechanical and chemical degradation. Among the principal failure mechanisms, cathodic blistering is strongly influenced by diffusion, interfacial stresses, and tribological loading. This review therefore links cathodic blister evolution with coating degradation under combined tribological and corrosive conditions. The review critically examines the Khan–Nazir meso-mechanics Models I, II, and III, which integrate stress-assisted diffusion, residual stress development, mixed-mode fracture, and coating–substrate delamination. Recent developments have extended these models through substrate deformation, multilayer coating architectures, and electro-chemo-mechanical phase-field simulations. The models demonstrate how diffusion-induced and residual stresses interact with tribological loading to initiate and propagate interfacial defects. The analysis shows that blister evolution is primarily governed by elastic modulus mismatch and friction-induced stress fields, while stability criteria predict non-axisymmetric blister morphologies associated with buckling and delamination. Overall, this review highlights the significance of the Khan–Nazir models for understanding wear, friction, and coating durability in engineering systems. The unified framework provides valuable guidance for the design and optimisation of advanced multilayer protective coatings for marine, automotive, energy, and manufacturing applications operating under rolling/sliding contact and tribo-corrosion environments. Full article

IN625-2NbC-2SiC composite coatings were successfully deposited on IN625 substrates using laser cladding technology. This study systematically explores the dependency of phase assemblage, microstructural characteristics, microhardness, and wear behavior on the applied laser power. Experimental results show that the phase composition of the coatings remains essentially unchanged across different power levels, primarily consisting of γ-(Ni, Cr), NbC, and SiC, with partial retention or reprecipitation of NbC particles. Under low laser power, local defects rich in Si and C appear in the coating, which is primarily attributed to insufficient melting or uneven dispersion of SiC particles. An optimal power of 1500 W results in a more homogeneous structure, better elemental distribution, and improved carbide dispersion. However, excessively high laser power may lead to excessive heat input, reduced cooling rate, and local microstructural inhomogeneity. Microhardness and tribological tests demonstrate that laser cladding significantly improves the surface properties of the IN625 substrate. The average microhardness values of the substrate, S1 to S4 are 250.5, 345.4, 357.2, 367.1, and 338.2 HV, respectively. Among them, the S3 coating exhibits the highest microhardness, which is approximately 46.5% higher than that of the substrate. Meanwhile, the S3 coating shows the lowest average friction coefficient and wear rate. The wear resistance ranking is as follows: S3 > S2 > S1 > S4 > substrate. The superior wear resistance of S3 is largely due to its high hardness, uniform structure, and well-distributed carbide reinforcements, which strengthen its resistance to deformation and abrasive wear. Based on overall consideration of phase, microstructure, and tribological performance, 1500 W is concluded to be the optimal laser power under the conditions investigated. Full article

Steel components in thermal power plants are vulnerable to severe wear and wall thinning induced by the high-velocity impact of pulverized coal, which significantly compromises their service life and structural integrity. To address this issue, a TiC-reinforced AlCoCrFeNi high-entropy alloy (HEA) composite coating was fabricated via laser cladding, aiming to substantially enhance the wear resistance of these critical components. The phase composition, microstructure, microhardness and tribological behaviors of the coatings were systematically investigated by XRD, SEM, EDS and dry sliding wear tests. Results show that both coatings possess dense microstructures and reliable metallurgical bonding with the substrate. The AlCoCrFeNi coating consists of a single BCC solid solution phase, while the TiC/AlCoCrFeNi composite coating contains a BCC phase and a TiC ceramic phase without brittle intermetallic compounds. The average microhardness of the TiC/AlCoCrFeNi composite coating was measured to be 823 HV_0.3, which is 85.66% greater than that of the AlCoCrFeNi coating (443 HV_0.3). Under identical wear test conditions, the AlCoCrFeNi coating exhibits a mass loss of 31.4 mg and a volumetric wear rate of 24 × 10⁻³ mm³/min, whereas the TiC/AlCoCrFeNi composite coating exhibits a mass loss of 15.6 mg and a wear rate of 13 × 10⁻³ mm³/min, corresponding to reductions of approximately 50.32% and 45.83%, respectively. The wear mechanism of the AlCoCrFeNi coating is dominated by severe abrasive wear coupled with adhesive wear, while the addition of TiC converts the wear mechanism into mild abrasive wear and oxidative wear. The incorporation of TiC particles effectively enhances the microhardness and reduces the mass loss, thereby contributing to a marked improvement in the wear properties of the laser-clad AlCoCrFeNi coating. This research provides experimental data and theoretical support for the engineering application of TiC/AlCoCrFeNi composite coatings on wear-resistant components in thermal power units. Full article

In this study, AA7068 aluminum matrix composites reinforced with TiB₂/TiC were fabricated via mechanical alloying and microwave sintering to investigate the influence of reinforcement content and sintering temperature on microstructure, mechanical properties, and dry sliding wear. Mechanical alloying refined powders, reducing D₅₀ from 51.5 µm (AA) to 22.5 µm (AC9) and enhancing dispersion and retention of TiB₂/TiC particles. XRD confirmed α-Al as the dominant matrix phase, preserved TiB₂ and TiC phases, and limited MgAl₂O₄/ZnAl₂O₄ spinel formation. Crystallite refinement and increased lattice microstrain were observed with the addition of reinforcement. Microhardness increased with reinforcement content and sintering temperature, reaching 122.2 HV_0.05 in AC9-2. At the same time, the highest compressive strength was observed in AC6-2 (431.05 MPa), indicating that optimal load-bearing depends on densification and interfacial integrity rather than hardness alone. AC9-2 exhibited the best wear resistance, with a cumulative specific wear rate of 2.723 × 10⁻⁴ mm³/Nm over 1000 m. SEM-EDS analysis revealed oxide-rich tribolayers, mechanically mixed layers, TiB₂/TiC fragments, and Fe-rich third-body debris, indicating wear is predominantly hardness-controlled but strongly influenced by microstructural factors. Overall, TiB₂/TiC hybrid reinforcement improves AA7068 wear resistance through combined hard-particle load-bearing, reduced penetration, tribolayer stability, and third-body effects, offering insight for high-performance hybrid aluminum composites. Full article

The development of transparent multifunctional coatings capable of combining optical properties with mechanical durability remains a significant challenge in advanced materials engineering. In this study, novel hybrid coatings based on a poly(vinyl butyral)/epoxy resin (PVB/epoxy) matrix reinforced with tungsten disulfide (WS₂) nanostructures were developed and examined for potential application in camouflage protection of glass surfaces. Camouflage aims to reduce the detectability of an object by minimizing the optical contrast between the object and its surrounding environment. For transparent substrates such as glass, this objective is particularly demanding because the transparency must be preserved while reducing unwanted surface reflection and optical signatures over relevant spectral ranges. For this purpose, in this research two types of nanostructures were investigated: fullerene-like nanoparticles (IF-WS₂) and inorganic nanotubes (INT-WS₂). The coatings were fabricated via ultrasonically assisted solution dispersion followed by casting over the glass plates and Teflon molds, and solvent evaporation. Structural, thermal, optical, and mechanical properties were systematically evaluated using SEM, FTIR, DSC, UV-Vis-NIR spectroscopy, gloss measurements, hardness testing, and cavitation wear resistance analysis. The incorporation of WS₂ nanostructures led to improved mechanical performance, with increased hardness and enhanced resistance to cavitation-induced wear. Optical characterization showed moderate reductions in reflectance and controlled transmittance in the visible and near-infrared regions, while overall transparency was maintained. The results indicate that WS₂ nanostructures contribute to both light scattering and absorption, leading to reduced specular reflection and improved optical masking potential. The findings demonstrate that hybrid PVB/epoxy/WS₂ coatings offer a promising approach for designing transparent, mechanically resistant coatings with tunable optical properties, with potential applications in protective glass systems and advanced functional surfaces. Full article

This study investigates the microstructural evolution, mechanical performance, and electrochemical corrosion behavior of nanocrystalline boride layers formed on an Fe-20Cr-5Al ferritic alloy by pack boriding at 950 °C for 4 h. X-ray diffraction (XRD) and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) analyses confirmed the formation of a hierarchical boride layer approximately 80–85 μm in thickness, consisting of orthorhombic (Fe,Cr)B and tetragonal (Fe,Cr)₂B phases at the surface and (Fe,Cr)₂₃(C,B)₆ carboboride phases in the diffusion zone, the latter attributed to the carbon push-ahead mechanism. Rietveld refinement yielded a quantitative phase fraction of 51.9 wt.%. (Fe,Cr)B, 46.1 wt.% Fe₂B, and 2.0 wt.% (Fe,Cr)₂₃(C,B)₆, with a theoretical boride layer density of 7.40 g cm⁻³. Williamson–Hall analysis yielded an average crystallite size of 50.7 nm and a microstrain of 1.686 × 10⁻³, confirming the nanocrystalline character of the boride phases. Mechanical evaluation revealed a ~9-fold increase in surface hardness in Fe20Cr5Al-B relative to Fe20Cr5Al, reaching 1854 HV (18.18 GPa). Tribological testing demonstrated an ~18-fold reduction in wear rate (from 3.29 × 10⁻⁴ to 1.82 × 10⁻⁵ mm³/m) and a 14.5% reduction in the coefficient of friction (0.76→0.65), confirming the effectiveness of the boride layer as a tribological barrier. However, electrochemical analyses in 5 wt.% H₂SO₄ revealed a paradoxical deterioration in corrosion resistance: despite a noble shift in E_corr from −0.459 to −0.295 V, the corrosion rate increased ~4-fold (from 9.67 × 10⁻³ to 3.83 × 10⁻² mm/year), driven by Al-repulsion-induced passive film loss and micro-galvanic cell formation through micro-crack and porosity networks. These findings emphasize that while pack-boriding is highly effective for tribological enhancement of FeCrAl alloys, minimizing boride layer defects is essential to achieve concurrent corrosion protection in acidic environments. Full article

Background: Metallic orthopedic implants face persistent clinical challenges that have proved resistant to incremental conventional development. Machine learning and artificial intelligence offer a complementary paradigm for navigating the high-dimensional design spaces governing implant performance, yet the literature remains fragmented across disciplinary silos with no comprehensive synthesis spanning the full development pipeline. Methods: A structured database search of PubMed/MEDLINE, Embase, and Cochrane (executed May 2026), supplemented by hand-searching of reference lists, identified 33 primary studies organized across five sequential domains: alloy composition discovery, additive manufacturing process–property optimization, lattice and porous structure design, surface engineering and coatings, and corrosion and wear prediction. Results: Across all five domains, machine learning approaches, including random forests, convolutional neural networks, Bayesian optimization, generative adversarial networks, physics-informed neural networks, and autonomous multi-agent platforms, have accelerated property prediction and design space exploration beyond experimental or simulation-based methods. Shared barriers to translation include small, heterogeneous datasets, reliance on internal rather than external validation, limited interpretability, and the absence of regulatory frameworks for AI-assisted device design. Representative performance included modulus predictions within ~4 GPa of first-principles values, ML-designed alloys reaching ~42.7 GPa (versus 103–120 GPa for Ti-6Al-4V), property prediction R² often above 0.90 (up to 0.96–0.9991), 98.3% corrosion severity classification accuracy, and acceleration from a roughly fivefold reduction in finite element simulations to surrogates compressing days into minutes. Conclusions: Addressing these limitations will require open standardized databases linking materials parameters to registry-level clinical outcomes, prospective clinical validation studies, and coordinated engagement between researchers, industry, and regulatory agencies. Full article

High manganese steel jaw plates serve as the core structural components of jaw crushers. Subjected to continuous impact and compressive loads during crushing service, they demand superior wear resistance and impact fatigue performance. In this work, laser cladding was employed to fabricate CeO₂-reinforced Fe60 composite coatings on ZGMn13 high manganese steel jaw plate substrate. The surface modification effects were systematically investigated in terms of macroscopic structure analysis, hardness property testing, and wear resistance evaluation. Composite coatings with CeO₂ mass fractions of 0%, 1%, 2%, and 3% were prepared, and their microstructures and morphologies were characterized by visual inspection, optical microscopy, and scanning electron microscopy. The test results indicate that the dendritic structures became more pronounced with increasing CeO₂ content; however, fracture marks occurred when the CeO₂ content was below 1%. A Rockwell hardness tester was adopted to measure coating hardness under a load stress of 382.44 MPa, and the results demonstrate that coating hardness presents a positive correlation with CeO₂ doping content. Furthermore, pin-on-disc friction and wear tests were conducted on the prepared coatings. The optimized CeO₂-modified coating achieved a minimum wear rate of 0.0033 mm³/(N·m), which is 78.6% lower than that of the untreated substrate. This work provides a valuable reference for improving the surface hardness and wear resistance of jaw plates and promotes the engineering application of laser cladding technology in wear-resistant component strengthening. Full article

Wire Laser Additive Manufacturing (WLAM) has emerged as a promising alternative for the fabrication and repair of components subjected to severe wear conditions due to its high deposition rate, efficient material utilization, and localized thermal control. In this study, the WLAM process using DUR600 wire as the feedstock material for the deposition of abrasion-resistant coatings was investigated. The deposited specimens were characterized by optical emission spectroscopy (OES), X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDS), Vickers microhardness testing, and dry sand/rubber wheel abrasion testing in accordance with ASTM G65. The deposits exhibited a predominantly martensitic microstructure with retained austenite, as confirmed by XRD. Hardness values ranged from 749 to 817 HV, with an average of 783 ± 18 HV, while the average volumetric loss in the abrasive wear test was 150.26 mm³. This behavior was attributed to the presence of the martensitic matrix and retained austenite, whose combined effect directly influences the tribological performance of WLAM coatings produced using DUR600 wire. Full article

In this study, a sustainable advanced manufacturing technology was developed using a holistic approach for finishing heat-treated 42CrMo4 steel cylindrical parts. The proposed technology is based on a hybrid combined process (HCP) involving cool-assisted dry hard turning and subsequent cool-assisted dry diamond burnishing (DB). A cold-air cooling (without lubrication) condition was achieved using a special device with a cold-air nozzle based on the principle of vortex tubes. The study was conducted in two stages. In the first stage, only the hard turning process was investigated using variance analysis to determine the significant governing factors (feed rate and cutting insert radius). The second stage involved studying and optimising the HCP. This approach incorporated the two significant turning process factors, along with three additional DB process factors: the radius of the diamond insert, burnishing force and feed rate. The selected objective functions were the average roughness, skewness, kurtosis, surface microhardness, residual surface axial stress and fatigue limit. The fatigue limit was determined using the accelerated Locati method. Mathematical models of the objective functions were obtained using experiments and regression analyses. Using multi-objective optimisation, the HCP was optimised based on two criteria: (1) maximum wear resistance under boundary lubrication conditions and (2) maximum fatigue limit. The optimisation tasks were solved by searching for the Pareto optimal solution approach using QStatLab and the NSGA II algorithm. The compromise optimal values of the governing factors, maximising the fatigue limit (690 MPa), are as follows: feed rate in turning and DB of 0.05 mm/rev, radius of the cutting insert of 0.8 mm, diamond insert radius of 2 mm, and burnishing force of 50 N. Experimental verification showed a good agreement with the optimised solutions for surface integrity and fatigue limit characteristics. Full article

Cobalt–chromium (CoCr) alloys have gained significant importance in the field of medical implants due to their outstanding combination of mechanical strength and excellent wear and corrosion resistance. Compared with other state-of-the-art materials, such as stainless steel or titanium, CoCr alloys typically exhibit superior fatigue strength, which is particularly advantageous for implants and components exposed to long-term repetitive loading. The present study investigates the feasibility of using commercially available CoCr alloy powders in the Laser Powder Bed Fusion (PBF-LB/M) process for the fabrication of biomedical implants. Microstructural characterization of the PBF-LB/M-manufactured CoCr samples revealed a dense, refined cellular–dendritic microstructure with a high degree of densification, characteristic of the rapid solidification associated with the PBF-LB/M process. The evaluation of mechanical performance, wear behavior, and corrosion resistance provides valuable insights into the suitability of these alloys for biomedical applications, especially in the design of complex implants requiring enhanced durability and long-term reliability. Furthermore, compression testing highlighted the influence of layer orientation on mechanical properties, emphasizing the importance of strategic prototyping and building orientation selection in the PBF-LB/M process. Tribological behavior assessed under dry sliding conditions demonstrated a significantly reduced coefficient of friction and lower wear rate compared to a conventional 316L stainless steel, which is frequently used in similar applications. Corrosion resistance was evaluated by potentiodynamic polarization measurements in Ringer electrolyte, showing that the PBF-LB/M-fabricated CoCr samples exhibit good corrosion resistance in environments resembling physiological fluids. Overall, the PBF-LB/M technique represents a promising manufacturing route for next-generation CoCr biomedical implants, particularly for orthopedic and dental applications. Beyond the biomedical field, the findings of this study also support the potential extension of PBF-LB/M-processed CoCr alloys to industrial sectors requiring high wear and corrosion resistance, including aerospace and automotive applications. Full article

The Böhme abrasion test (EN 14157) is widely used to evaluate the wear resistance of natural stones; however, the abrasive powder specified by TS 699 requiring 70–80 wt.% crystalline Al₂O₃ is not commercially available in the Turkish market. Commercially supplied abrasives deviate substantially from both the prescribed chemical composition and the grain-size distribution of TS 699, introducing a recognized but unresolved source of variability in Böhme abrasion measurements. This study evaluates the influence of abrasive type and particle-size distribution on Böhme abrasion performance with the aim of identifying which available abrasive material yields the most reliable and reproducible test results. The emphasis is therefore metrological—on test repeatability and standardization—rather than on ranking the abrasion resistance of the stones. Six natural stones representing contrasting lithologies—four crystalline marbles, one limestone, and one granite—were tested using five abrasive powders: two locally produced natural emery abrasives (Emery-1 and Emery-2), silicon carbide (SiC), white corundum, and brown corundum. Each abrasive was evaluated under both standardized graded conditions prepared in accordance with TS 699 and heterogeneous ungraded conditions reflecting common industrial practice. Chemical analyses confirmed that both emery abrasives deviate markedly from TS 699 specifications, with Al₂O₃ contents (~57.7 wt.%) well below the required range and Fe₂O₃ (~24 wt.%) considerably exceeding the standard limit. Sieve analyses further revealed substantial particle-size deviations in several commercial abrasives. One-way ANOVA demonstrated that abrasive type exerts a statistically significant influence on abrasion performance (F = 8.99, p < 0.05, η² = 0.297). SiC consistently produced the highest abrasion values, followed by corundum-based abrasives, while emery abrasives showed comparatively lower but stable performance. Independent-samples t-tests showed that particle-size grading significantly affected abrasion performance only for brown corundum (p < 0.05), attributable to its markedly elevated coarse particle fraction. Petrographic analysis, XRD, and SEM–EDS characterization of the investigated rocks confirmed that abrasion response is additionally modulated by rock mineralogy and microstructure. Under standardized grading conditions, SiC provided the most consistent and reproducible results across all lithologies, supporting its suitability as the reference abrasive for inter-laboratory Böhme testing. Locally produced emery abrasives, despite their chemical non-compliance with TS 699, yielded stable and reproducible outcomes under controlled grading, supporting their potential as cost-effective alternatives for routine testing. Full article

Friction stir processing (FSP) was applied to rolled 65Mn steel to improve its surface wear resistance, with untreated and conventionally water-quenched specimens used as reference conditions. A 3 × 3 full-factorial combination of rotational speeds of 600, 700, and 800 rpm and traverse speeds of 200, 250, and 300 mm/min was investigated. Continuous modified layers without obvious macroscopic defects were obtained under all processing conditions. FSP substantially fragmented and reconstructed the original ferrite–pearlite microstructure, producing a fine and relatively homogeneous acicular/lath-like transformed microstructure. The average grain size decreased from 27.1 μm to 11.6–17.2 μm, corresponding to reductions of 36.5–57.2%, while the high-angle grain-boundary fraction increased from 76.7% to a maximum of 86.2%. Although the hardness of the FSP-treated regions was comparable to that of the quenched specimen, FSP produced a more continuous and spatially uniform gradient-hardened layer. The minimum wear rate was obtained at 800 rpm and 200 mm/min, representing reductions of 97.34% and 96.14% relative to the base material and quenched specimen, respectively. The condition of 800 rpm and 300 mm/min was identified as the optimum overall condition because it provided a favorable balance among wear rate, mass loss, hardened-layer continuity, and wear-track morphology, with wear-rate reductions of 96.57% and 95.02% and mass-loss reductions of 66.67% and 57.14% relative to the two reference conditions. The improved wear resistance is primarily associated with grain refinement, grain-boundary reconstruction, microstructural homogenization, and the formation of a continuous gradient-hardened layer. Full article