In this work,a novel process,oscillatory pressure-assisted sinter forging(OPSF),for the preparation of high-performance ceramic composites was *** with the samples made by conventional sinter forging(SF)and hot oscill...
详细信息
In this work,a novel process,oscillatory pressure-assisted sinter forging(OPSF),for the preparation of high-performance ceramic composites was *** with the samples made by conventional sinter forging(SF)and hot oscillatory pressing(HOP),the SiC whisker reinforced Al_(2)O_(3) composites(SiCw–Al_(2)O_(3))prepared by OPSF at the same temperature exhibited a higher density and significantly improved the mechanical *** improvements in densification and performance are attributed to simultaneous enhanced shear deformation at both macro-and micro-scales,resulting from the combination of die-free configuration and oscillatory pressure of *** the strength of grain boundary is greatly increased when the temperature reaches 1600℃ of OPSF,due to that the grain-boundary sliding became pronounced at higher *** current results shed light on a powerful technique for preparing ceramic composites,which is likely applicable to other systems.
Adhesively Bonded Carbon Fibre Reinforced Plastic(CFRP)and titanium alloy have been extensively used as a hybrid structure in modern aircrafts due to their excellent combination of mechanical properties and chemical *...
详细信息
Adhesively Bonded Carbon Fibre Reinforced Plastic(CFRP)and titanium alloy have been extensively used as a hybrid structure in modern aircrafts due to their excellent combination of mechanical properties and chemical *** study utilised NaOH anodising method to create micro-rough titanium surfaces for enhancing adhesive bonding between titanium alloy and CFRP laminates.A special and simple technique named Resin Pre-Coating(RPC)was also employed to improve the surface wetting of anodised titanium and grinded CFRP *** influences of anodising temperature and duration on the surface morphology,wettability and adhesive bond strength were *** single lap shear test results showed that the bond strength of specimens anodised at 20℃for 15 min improved by 135.9%and 95.4%,respectively,in comparison with that of acid pickled and grinded specimens(without RPC treatment).Although increasing the anodising temperature and duration produced rougher titanium surfaces,the adhesively bonded joints were not strong enough due to relatively friable titanium oxide layers.
Large-density functional theory(DFT)databases are a treasure trove of energies,forces,and stresses that can be used to train machine-learned interatomic potentials for atomistic ***,we employ structural relaxations fr...
详细信息
Large-density functional theory(DFT)databases are a treasure trove of energies,forces,and stresses that can be used to train machine-learned interatomic potentials for atomistic ***,we employ structural relaxations from the AFLOWdatabase to train moment tensor potentials(MTPs)for four carbide systems:CHfTa,CHfZr,CMoW,and *** resulting MTPs are used to relax~6300 random symmetric structures,and are subsequently improved via active learning to generate robust potentials(RP)that can relax a wide variety of structures,and accurate potentials(AP)designed for the relaxation of low-energy *** protocol is shown to yield convex hulls that are indistinguishable from those predicted by AFLOWfor the CHfTa,CHfZr,and CTaTi systems,and in the case of the CMoW system to predict thermodynamically stable structures that are not found within AFLOW,highlighting the potential of the employed protocol within crystal structure *** of over three hundred(Mo1−xWx)C stoichiometry crystals first with the RP then with the AP yields formation enthalpies that are in excellent agreement with those obtained via DFT.
The Subsea Shuttle Tanker (SST) was presented by the authors as an innovative and cost-effective solution in several research works. This new approach offers a viable alternative to subsea pipelines and shuttle tanker...
详细信息
The hydrogen-induced delayed fracture(HIDF)behavior of a 1300-MPa-grade high-strength bolt steel 42CrMoV containing 0.42 wt.%Cu was investigated by constant load tensile test in a pH 3.5 Walpole *** is shown that the ...
详细信息
The hydrogen-induced delayed fracture(HIDF)behavior of a 1300-MPa-grade high-strength bolt steel 42CrMoV containing 0.42 wt.%Cu was investigated by constant load tensile test in a pH 3.5 Walpole *** is shown that the addition of Cu is beneficial to enhance the HIDF resistance by~13%.The observation of the fracture surface revealed that the area fraction of brittle crack initiation zone decreased remarkably for the Cu-added *** the corrosion pit depth and the corrosion rate of the Cu-added steel in the Walpole solution are notably decreased,which is primarily because of the formation of a Cu-rich protective compact rust layer and slightly higher corrosion *** a result,the absorbed hydrogen content in that solution was also decreased by~21%.It is concluded that the improvement in the HIDF resistance of the tested steel is primarily due to the increase in corrosion resistance and resultant decrease in the absorbed diffusible hydrogen content in the acidic condition.
Effective fault diagnosis has a crucial impact on the safety and cost of complex manufacturing ***,the complex structure of the collected multisource data and scarcity of fault samples make it difficult to accurately ...
详细信息
Effective fault diagnosis has a crucial impact on the safety and cost of complex manufacturing ***,the complex structure of the collected multisource data and scarcity of fault samples make it difficult to accurately identify multiple fault *** address this challenge,this paper proposes a novel deep-learning model for multisource data augmentation and small sample fault *** raw multisource data are first converted into two-dimensional images using the Gramian Angular Field,and a generator is built to transform random noise into images through transposed convolution ***,two discriminators are constructed to evaluate the authenticity of input images and the fault diagnosis *** Vision Transformer network is built to diagnose faults and obtain the classification error for the ***,a global optimization strategy is designed to upgrade parameters in the *** discriminators and generator compete with each other until Nash equilibrium is achieved.A real-world multistep forging machine is adopted to compare and validate the performance of different *** experimental results indicate that the proposed method has multisource data augmentation and minority sample fault diagnosis *** with other state-of-the-art models,the proposed approach has better fault diagnosis accuracy in various scenarios.
The in-situ growing approach was utilized in this article to construct the magnesium–aluminum layered double hydroxide(MgAl-LDH)film on the surface of a 1060 aluminum anodized *** improve the corrosion resistance and...
详细信息
The in-situ growing approach was utilized in this article to construct the magnesium–aluminum layered double hydroxide(MgAl-LDH)film on the surface of a 1060 aluminum anodized *** improve the corrosion resistance and friction qualities of aluminum alloy,the MgAl-LDH coating was treated using stearic acid(SA)and thiourea(TU).The aluminum substrate and anodized aluminum film layer corroded to varying degrees after 24 h of immersion in 3.5%(mass)NaCl solution,while the modified hydrotalcite film layer continued to exhibit the same microscopic morphology even after being immersed for 7 *** results show that the synergistic action of thiourea and stearic acid can effectively improve the corrosion resistance of the MgAl-LDH *** tribological testing reveals that the hydrotalcite film layer and the modified film layer lowered the friction coefficient of the anodized aluminum surface *** results of the simulations and experiments demonstrate that SA forms the dense LDH-TU interlayer film layer by exchanging NO_(3)^(-)ions between TU layers on the one hand and the LDH-SA film layer by adsorption on the surface of LDH on the ***,these two processes create LDH-TUSA,which can significantly increase the substrate’s corrosion *** synergistically modified superhydrophobic and retardant hydrotalcite film layer offers a novel approach to the investigation of wear reduction and corrosion protection on the surface of aluminum and its alloys.
Automobiles are the inevitable mode of ***,increasing fuel prices and carbon dioxide emissions are posing a serious threat to automobile users and the ***,the development of new lightweight materials has been a key ar...
详细信息
Automobiles are the inevitable mode of ***,increasing fuel prices and carbon dioxide emissions are posing a serious threat to automobile users and the ***,the development of new lightweight materials has been a key area of ***-based commercial alloys(AZ and ZK series alloys)are the lightest among all structural ***,there is still a question about the replacement of Aluminum-based alloys due to HCP crystal *** this connection,Mg-Al-Ca-Mn(AXM)Mg alloy can be a choice as an alternative to the existing Mg-based commercial alloys for structural *** contains(Al,Mg)_(2)Ca,Al_(2)Ca,Mg_(2)Ca,and Al_(8)Mn_(5)as the secondary phases,contributing to the microstructural refinement and property ***,the formation of those precipitates depends on the amount of Al,Ca,and Mn,especially,the Ca/Al *** addition,the secondary processes influence the grain refinement and property enhancement of texture ***,this review article focuses on elaborating on the significance of the Ca/Al ratio for the precipitate formation,secondary process,and texture *** co-segregation behavior of other micro-alloying elements like Cerium,Lanthanum,and Zinc in AXM Mg alloy systems has also been discussed for property enhancement.
With the rapid development of the electronics industry,the demand for dielectric materials with high permittivities,low losses,and excellent electrical breakdown strengths prepared via low-temperature fabrication tech...
详细信息
With the rapid development of the electronics industry,the demand for dielectric materials with high permittivities,low losses,and excellent electrical breakdown strengths prepared via low-temperature fabrication techniques is ***,we propose a one-step cold sintering process route to improve the comprehensive performance of BaTiO_(3)−based ceramics by integrating polyetherimide(PEI).Dense BaTiO_(3)–PEI nanocomposites can be prepared via a cold sintering process at 250℃ using Ba(OH)_(2)∙8H_(2)O and H_(2)TiO_(3) as the transient liquid *** grain growth of BaTiO_(3) is inhibited,and thin PEI layers less than 10 nm in size are located at the grain *** dissolution‒precipitation process triggered by the transient liquid phase and viscous flow assisted by PEI dominates the cold sintering mechanism of the(1−x)BaTiO_(3)–xPEI *** dielectric properties are stable over a broad temperature range up to 200℃.Compared with BaTiO_(3),80%BaTiO_(3)–20%PEI has superior performance,with a relative permittivity of 163 and a low dielectric loss of 0.014,and the electrical breakdown strength is increased by 80.65%compared with BaTiO_(3).Overall,the cold sintering process provides a potential way to develop dielectric nanocomposites with excellent comprehensive performance.
Designing strong, yet ductile, and body-centered cubic(BCC) medium-entropy alloys(MEAs) remains to be a challenge *** this study, the strength–ductility trade-off of Ni_(0.6)CoFe_(1.4)MEAs was tackled via introducing...
详细信息
Designing strong, yet ductile, and body-centered cubic(BCC) medium-entropy alloys(MEAs) remains to be a challenge *** this study, the strength–ductility trade-off of Ni_(0.6)CoFe_(1.4)MEAs was tackled via introducing a BCC + face-centered cubic(FCC) dual-phase microstructure. Ni_(0.6)CoFe_(1.4)Nbx(x = 0, 0.05, 0.08, 0.10, and 0.15, in molar ratio) MEAs were prepared using vacuum induction melting. Results show that the new alloy is composed of BCC plus FCC dual phases featuring a network-like structure, and the BCC phase is the main phase in this alloy system. Moreover, the Nb0.10 MEA shows high strength and respectable tensile ductility, representing the best combination of the strength and fracture elongation among the alloys studied here. The remarkable strength of the Nb0.10 MEA is attributed to the combined effect of the solid solution strengthening, the precipitation hardening effect and the interface strengthening effect.
暂无评论