***Twinning is a fundamental mechanism for plastic deforma-tion in many face-centered cubic(FCC)metals having low stack-ing fault energies(SFEs)[1,2].
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Twinning is a fundamental mechanism for plastic deforma-tion in many face-centered cubic(FCC)metals having low stack-ing fault energies(SFEs)[1,2].
Hydrogen embrittlement in metals (HE) is a serious challenge for the use of high strength materials in engineering practice and a major barrier to the use of hydrogen for global decarbonization. Here we describe the f...
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The primary objective of global studies is to develop the properties and durability of polymers for various *** it comes to dental disability,denture base materials must have sufficient mechanical and tribological per...
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The primary objective of global studies is to develop the properties and durability of polymers for various *** it comes to dental disability,denture base materials must have sufficient mechanical and tribological performance in order to withstand the forces experienced in the *** work aims to investigate the effects of the addition of low content of cellulose nanocrystals(CNC)on the mechanical and tribological performance of the polymethyl methacrylate(PMMA)*** weight percent of CNC(0,0.2,0.4,0.6,and 0.8 wt%)were added to the PMMA matrix followed by ball milling to evenly distribute the nanoparticles reinforced phase in the matrix *** findings emphasize the significant impact of CNC integration on the performance of PMMA *** increasing the content of the CNC nanoparticles,the mechanical properties of PMMA were *** addition,the tribological outcomes demonstrated a significant reduction in the friction coefficient besides an enhancement in the wear resistance as the weight percentage of nanoparticles *** surface of the worn samples was investigated by utilizing SEM to identify the wear mechanisms corresponding to the different *** addition,a finite elment model(FEM)was developed to ascertain the thickness of the worn layer and the generated stressed on the surfaces of the nanocomposite throughout the friction process.
The precipitate morphologies,coarsening kinetics,elemental partitioning behaviors,grain structures,and tensile properties were explored in detail for L1_(2)-strengthened Ni_(39.9)Co_(20)Fe_(15)Cr_(15)Al_(6)Ti_(4-x)Nb_...
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The precipitate morphologies,coarsening kinetics,elemental partitioning behaviors,grain structures,and tensile properties were explored in detail for L1_(2)-strengthened Ni_(39.9)Co_(20)Fe_(15)Cr_(15)Al_(6)Ti_(4-x)Nb_(x)B_(0.1)(x=0 at.%,2 at.%,and 4 at.%)high-entropy alloys(HEAs).By substituting Ti with Nb,the spheroidal-to-cuboidal precipitate morphological transition,increase in the coarsening kinetics,and phase decomposition upon aging at 800°C *** excessive addition of Nb brings about the grain boundary precipitation of an Nb-rich phase along with the phase decomposition from the L1_(2)to lamellar-structured D019 phase upon the long-term aging *** partially substituting Ti with Nb,the chemically complex and thermally stable L12 phase with a composition of(Ni_(58.8)Co_(9.8)Fe_(2.7))(Al_(12.7)Ti_(5.8)Nb_(7.5)Cr_(2.3))ensures the stable phase structure and clean grain boundaries,which guarantees the superb high-temperature mechanical properties(791±7 MPa for yielding and 1013±11 MPa for failure)at 700℃.Stacking faults(SFs)were observed to prevail during the plastic deformation,offering a high work-hardening capability at 700°*** anomalous rise in the yield strength at 800℃was found,which could be ascribed to the multi-layered super-partial dislocations with a cross-slip configuration within the L1_(2)particles.
The square wave polarisation technique and mathematical/electrochemical models were combined to investigate pitting corrosion of pipeline steel X100 under cathodic protection potential fluctuations with different duty...
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The square wave polarisation technique and mathematical/electrochemical models were combined to investigate pitting corrosion of pipeline steel X100 under cathodic protection potential fluctuations with different duty cycles（δ）. Mathematical equations were derived to describe the increased potential of the double-charge layer at the steel/solution interface, which increases density from 1100 mm-2（δ = 10%） to over 6600 mm-2（δ = 50%）. However, an electrochemical model was developed to present the formation of an amorphous corrosion product layer,which reduces the number of local anodic corrosion areas and decreases pitting density when δ is higher than 50%.
Coherent precipitation of cuboidal γ'-Co3(Al,W) nanoparticles in face-centered-cubic (FCC)-γ matrix is of great significance for improving high-temperature mechanical properties of Co-based superalloys. The pres...
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Coherent precipitation of cuboidal γ'-Co3(Al,W) nanoparticles in face-centered-cubic (FCC)-γ matrix is of great significance for improving high-temperature mechanical properties of Co-based superalloys. The present work developed a series of low-density Co-based superalloys in light of the cluster composition formula of [Al1-(Co,Ni)12]((Al0.5(Ti/Nb/Ta)0.5W0.5)(Mo0.5Cr0.5Co0.5)), where the addition of Ti, Nb, and Ta is mixed with an equimolar ratio. It is found that these designed alloys with different combinations of Ti/Nb/Ta, Ti/Nb, and Ti/Ta possess the coherent microstructure of cuboidal γ' nanoprecipitates in the FCC-γ matrix. The microstructural evolution of coherent γ/γ' during aging at 1173 K shows that these superalloys exhibit higher thermal stability at high temperatures. Even after aging for 1000 h, there do not exist any other precipitated phases on grain boundaries, except the coarse γ' precipitates. Also, the coarsening rate constants of cuboidal γ' nanoprecipitates in these alloys are very low (K = 5.76-6.03 nm3/s), which is mainly ascribed to a moderate lattice misfit (ε = 0.28 %-0.45 %) between γ and γ'. The stable γ/γ' microstructure renders the alloys with prominent mechanical properties, as evidenced by the high yield strength of σYS = 438-445 MPa at 1143 K. A large amount of stacking faults appear after compressive deformation and Lomer-Contrell dislocation locks are also formed due to the reaction of partial dislocations of stacking faults. Moreover, the microhardness (285-320 HV) in each alloy keeps almost constant with the aging time. Besides, these superalloys have a relatively lower density (8.67-8.89 g/cm3), among which the alloy containing Ti0.25Ta0.25 also exhibits a much higher γ' solvus temperature (1361 ± 2 K) than those of the existing Co-Al-W-based superalloys.
In this paper,two ways of micro structural characterization,optical microscopy(OM) and polarized light microscopy(PLM),were both employed to describe the micro structure of semisolid slurry prepared by swirling enthal...
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In this paper,two ways of micro structural characterization,optical microscopy(OM) and polarized light microscopy(PLM),were both employed to describe the micro structure of semisolid slurry prepared by swirling enthalpy equilibration device(SEED).The results show that PLM is more reliable and accurate than OM to describe the special morphology feature of semisolid slurry made by SEED ***,the effects of pouring temperature and mass of molten liquid on the primary α-Al particle size and morphology were also investigated using *** quantitative metallographic results measured from PLM demonstrate that the grain size and morphology and their distribution are significantly affected by both pouring temperature and the mass of molten *** grain size poured with 2.7 kg liquid decreases from 659 to186 μm,and grain morphology transforms from dendrite to globular structure with pouring temperature reducing from690 to 630℃.The decreasing pouring temperature also promotes the distribution of spherical structure on the cross ***,the mass of molten liquid decreasing from 2.7 to 2.3 kg can decrease the grain size by maximum of 44% at high pouring temperature.
Low-dimensional multiferroics,which simultaneously possess at least two primary ferroic order parameters,hold great promise for post-Moore electronic ***,intrinsic onedimensional(1D)multiferroics with the coexistence ...
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Low-dimensional multiferroics,which simultaneously possess at least two primary ferroic order parameters,hold great promise for post-Moore electronic ***,intrinsic onedimensional(1D)multiferroics with the coexistence of ferroelectricity and ferromagnetism are still yet to be realized,which will be not only crucial for exploring the interplay between low-dimensionality and ferroelectric/ferromagnetic ordering but also significant in rendering application approaches for high density information technologies.
Conventional synthetic materials have fixed mechanical properties and suffer defects,damage,and degradation over *** makes them unable to adapt to changing environments and leads to limited ***,self-adaptive materials...
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Conventional synthetic materials have fixed mechanical properties and suffer defects,damage,and degradation over *** makes them unable to adapt to changing environments and leads to limited ***,self-adaptive materials inspired by natural materials have emerged as a solution to address these *** the ability to change their mechanical properties based on changing mechanical environments,repairing defects,and maintaining their mechanical properties,these materials can lead to improved performance while decreasing *** this review,we explore self-adaptive phenomena found in nature that have inspired the development of synthetic self-adaptive materials,and the mechanisms that have been employed to create the next generation of *** potential applications of these materials,the challenges that existing approaches face,and future research opportunities are also discussed.
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