The growing need for stronger and more ductile structural materials has spurred an intense search for innovative,high-performance ***,alloys face a pervasive trade-off:high strength often comes at the expense of ducti...
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The growing need for stronger and more ductile structural materials has spurred an intense search for innovative,high-performance ***,alloys face a pervasive trade-off:high strength often comes at the expense of ductility and vice *** advent of high-entropy alloys(HEAs)offering both high strength and ductility has transformed this *** this work,we discuss the deformation mechanisms of HEAs,examine the foundations of the strength-ductility trade-off,and explore approaches for designing HEAs to surmount this ***,we analyze the factors that govern HEA-deformation performance,which in turn influence the HEA *** also propose a perspective on future research directions concerning the mechanical behavior of HEAs,highlighting potential breakthroughs and novel strategies to advance the field.
Triboelectric nanogenerators(TENGs) are emerging as new technologies to harvest electrical power from mechanical *** the distinctive working mechanism of triboelectric nanogenerators,they attract particular interest i...
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Triboelectric nanogenerators(TENGs) are emerging as new technologies to harvest electrical power from mechanical *** the distinctive working mechanism of triboelectric nanogenerators,they attract particular interest in healthcare monitoring,wearable electronics,and deformable energy harvesting,which raises the requirement for highly conformable devices with substantial energy outputs.
Under the laser directed energy deposition(LDED)process,the rapid melting and solidification usually lead to the emergence of pores and coarse columnar dendrites,which in turn compromise the properties of the deposite...
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Under the laser directed energy deposition(LDED)process,the rapid melting and solidification usually lead to the emergence of pores and coarse columnar dendrites,which in turn compromise the properties of the deposited *** study introduced in-situ ultrasonic rolling(UR)as an innovative method to enhance the corrosion resistance of LDED specimens,and the microstructural characteristics and their correlation with corrosion resistance were deeply *** findings reveal that the LDED-UR specimen exhibits a reduction in both the fraction and size of *** the influence of severe plastic deformation generated by LDED-UR process,fully equiaxed grains appear with a reduced average size of 28.61μm(compared to63.98μm for the LDED specimen with columnar grains).The electrochemical corrosion resistance of the LDED-UR specimen is significantly enhanced compared to the LDED *** enhanced corrosion resistance can be attributed to the low fraction of small-sized pores,the fine and uniformly distributed Cr-enriched ferrite phase,and the formation of a compact and thick passive film due to dense grain *** insight of the correlation between microstructure and corrosion behavior opens up a new pathway to enhance the corrosion resistance of LDED specimens.
The welding characteristics of 5052 aluminum alloy and Q235 low-carbon steel sheet were systematically studied by the refilled friction stir spot *** effects of rotation speed and pressure speed on weld forming,tensil...
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The welding characteristics of 5052 aluminum alloy and Q235 low-carbon steel sheet were systematically studied by the refilled friction stir spot *** effects of rotation speed and pressure speed on weld forming,tensile strength,and welded joint structure were analyzed in different welding *** results indicated two different connection modes:the chimeric mode and the non-chimeric *** corresponding depression depth are 2 and 2.4 mm,*** the non-chimeric connection mode,the steel/aluminum metallurgical interface is a smooth transition,the hook structure is obvious,and the welding mechanism mainly depends on the mutual diffusion between ***,in the chimeric mode,a hook structure will be formed at the metallurgical interface of steel and *** connection mechanism is determined by mechanical interlocking and mutual *** maximum strength value is 7.48 kN in non-chimeric *** this time,the spindle speed is 1300 r/min and the pressure speed is 1 mm/*** were two types of fractures:the button fracture mode and the peel fracture mode.
In recent years,modification of texture distribution has been considered a valid approach to improve the room-temperature(RT)formability of magnesium(Mg)*** this study,a novel Mgsingle bond2Znsingle bond3Lisingle bond...
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In recent years,modification of texture distribution has been considered a valid approach to improve the room-temperature(RT)formability of magnesium(Mg)*** this study,a novel Mgsingle bond2Znsingle bond3Lisingle bond1Gd alloy sheet with weak elliptical-texture was fabricated by cold rolling and subsequent annealing,and it showed an excellent Erichsen(IE)value near 7.1 *** quasi-in-situ electron backscatter diffraction(EBSD)and transmission electron microscopy(TEM)analysis indicate that considerable basal and pyramidal dislocations can be activated in the cold rolling *** annealing,these dislocations can induce nucleation and then cause preferential misorientation relationships around〈uvt0〉concerning the nuclei and parent grains,which can facilitate the formation of elliptical ***,the particle-stimulated nucleation(PSN)mechanism and the co-segregation of Zn and Gd at grain boundaries(GB)further weak texture ***,the mechanical properties of the Mgsingle bond2Znsingle bond3Lisingle bond1Gd alloy sheet are significantly improved.
Alumina-forming austenitic(AFA) steel, a promising candidate for use in high-temperature components of ultrasupercritical power plants, has high creep strengths and outstanding high-temperature corrosion resistance. T...
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Alumina-forming austenitic(AFA) steel, a promising candidate for use in high-temperature components of ultrasupercritical power plants, has high creep strengths and outstanding high-temperature corrosion resistance. The effects of microstructural evolution on the mechanical properties of Fe-20Ni-14Cr-3Al alumina-forming austenitic(3Al-AFA) steel with micro-cold deformation were investigated by multiple characterization methods, and the micro-cold deformation process was analyzed by conducting compression experiments. Tensile properties and hardness were also examined. The results show that the reduction of deformation has significant influences on the increase in the density of dislocation, the reduction of grain size, and the distribution of precipitates, which play an essential role in the enhancement of mechanical properties. As the reduction of deformation increases, the density of dislocations rises, the fragmentation of grains results in a reduction of grain size, and the distribution of precipitates at the grain boundaries gradually increases, which causes a rise in strength and a decrease in elongation. Since the elastic deformation range expands with an increase in deformation before the strain reaches 5 %of the CR0 sample in the compression test, the variation in the average grain aspect ratio between a reduction of 2% and 6 % is relatively small. It contributes more to hardness and strength when the grain aspect ratio is high.
Gradient nano-grained structure is frequently engineered into metallic materials,including Mg alloys,to achieve superior combination of strength and ***,the influence of this microstructural feature on aging precipita...
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Gradient nano-grained structure is frequently engineered into metallic materials,including Mg alloys,to achieve superior combination of strength and ***,the influence of this microstructural feature on aging precipitation behavior remains inadequately *** this study,the age-precipitation behavior of a gradient nano-grained Mg-Gd-Ag-Zr alloy prepared via ultrasonic severe surface rolling was *** result indicates that the aging precipitation behavior exhibits a depth-dependent variation within this *** the nano-grained surface layer,hierarchicalβnano-precipitates are predominant,while at greater depths,the precipitates consist ofβnanoparticles located at grain boundaries,along with intragranularβ′andγ″*** formation ofβnano-precipitates deviates from the conventional precipitation behavior observed in Mg-Gd-Ag alloys,and is attributed to the high density of defects induced by the surface nano-grained *** finding advances our understanding of the precipitation behavior in the alloys with heterogeneous microstructure.
Based on the advantages of triply periodic minimal surface(TPMS)porous structures,extensive research on NiTi shape memory alloy TPMS scaffolds has been ***,the current reports about TPMS porous structures highly rely ...
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Based on the advantages of triply periodic minimal surface(TPMS)porous structures,extensive research on NiTi shape memory alloy TPMS scaffolds has been ***,the current reports about TPMS porous structures highly rely on the implicit equation,which limited the design *** this work,novel shell-based TPMS structures were designed and fabricated by laser powder bed *** comparisons of manufacturability,mechanical properties,and shape recovery responses between traditional solid-based and novel shell-based TPMS structures were *** indicated that the shell-based TPMS porous structures possessed larger Young's moduli and higher compressive ***,Diamond shell structure possessed the highest Young's moduli of 605.8±24.5MPa,while Gyroid shell structure possessed the highest compressive strength of 43.90±3.32 *** addition,because of the larger specific surface area,higher critical stress to induce martensite transformation,and lower austenite finish temperature,the Diamond shell porous structure exhibited much higher shape recovery performance(only 0.1%residual strain left at pre-strains of 6%)than other porous *** results substantially uncover the effects of structural topology on the mechanical properties and shape recovery responses of NiTi shape memory alloy scaffolds,and confirm the effectiveness of this novel structural design *** research can provide guidance for the structural design application of NiTi porous scaffolds in bone implants.
To increase the processability and plasticity of the selective laser melting(SLM)fabricated Al-Mn-Mg-Er-Zr alloys,a novel TiB_(2)-modified Al-Mn-Mg-Er-Zr alloy with a mixture of Al-Mn-Mg-Er-Zr and nano-TiB_(2) powders...
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To increase the processability and plasticity of the selective laser melting(SLM)fabricated Al-Mn-Mg-Er-Zr alloys,a novel TiB_(2)-modified Al-Mn-Mg-Er-Zr alloy with a mixture of Al-Mn-Mg-Er-Zr and nano-TiB_(2) powders was fabricated by *** pro-cessability,microstructure,and mechanical properties of the alloy were systematically investigated by density measurement,microstruc-ture characterization,and mechanical properties *** alloys fabricated at 250 W displayed higher relative densities due to a uni-formly smooth top surface and appropriate laser energy *** maximum relative density value of the alloy reached(99.7±0.1)%,demonstrating good *** alloy exhibited a duplex grain microstructure consisting of columnar regions primarily and equiaxed regions with TiB_(2),Al6Mn,and Al3Er phases distributed along the grain *** directly aging treatment at a high tem-perature of 400℃,the strength of the SLM-fabricated TiB_(2)/Al-Mn-Mg-Er-Zr alloy increased due to the precipitation of the secondary Al6Mn *** maximum yield strength and ultimate tensile strength of the aging alloy were measured to be(374±1)and(512±13)MPa,*** SLM-fabricated TiB_(2)/Al-Mn-Mg-Er-Zr alloy demonstrates exceptional strength and thermal stability due to the synergistic effects of the inhibition of grain growth,the incorporation of TiB_(2) nanoparticles,and the precipitation of secondary Al6Mn nanoparticles.
Finite element (FE) coupled thermal-mechanical analysis is widely used to predict the deformation and residualstress of wire arc additive manufacturing (WAAM) parts. In this study, an innovative single-layermulti-bead...
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Finite element (FE) coupled thermal-mechanical analysis is widely used to predict the deformation and residualstress of wire arc additive manufacturing (WAAM) parts. In this study, an innovative single-layermulti-bead profilegeometric modeling method through the isosceles trapezoid function is proposed to build the FE model of theWAAMprocess. Firstly, a straight-line model for overlapping beads based on the parabola function was establishedto calculate the optimal center distance. Then, the isosceles trapezoid-based profile was employed to replace theparabola profiles of the parabola-based overlapping model to establish an innovative isosceles trapezoid-basedmulti-bead overlapping geometric model. The rationality of the isosceles trapezoid-based overlapping model wasconfirmed by comparing the geometric deviation and the heat dissipation performance index of the two overlappingmodels. In addition, the FE-coupled thermal-mechanical analysis, as well as a comparative experiment of thesingle-layer eight-bead deposition process show that the simulation results of the above two models agree with theexperimental results. At the same time, the proposed isosceles trapezoid-based overlappingmodels are all straightlineprofiles, which can be divided into high-quality FE elements. It can improve the modeling efficiency andshorten the simulation calculation time. The innovative modeling method proposed in this study can provide anefficient and high-precision geometricmodelingmethod forWAAMpart FE coupled thermal-mechanical analysis.
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