- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Effects of graphene coating on the plastic deformation of single crystal copper nano-cuboid under different nanoindentation modes
摘要： Molecular dynamic simulations of nanoindentation were performed to investigate the effects of graphene coatings on the plastic deformation of copper (Cu) under different indentation conditions. The results show that the graphene coating can dramatically strengthen the load bearing capability of Cu substrate for the displacement-controlled indentation, which is proportional to the number of graphene layers increasing from single to triple. And the load force also increases with the rising indentation speed, causing larger and rapider plastic deformation. For the load-controlled indentation, the graphene coating can protect the Cu substrate from being damaged by the external force. The protection capability of graphene increases as the layers growing to triple at the same loading. What's more, the larger load force can facilitate the increase in penetration depth at the equilibrium state. Our observation provide a better understanding of mechanism of plastic deformation under the effect of graphene covering.
关键词： Plastic deformation,Nanoindentation,Molecular dynamic simulations,Graphene coating
更新于2025-09-23 15:23:52
-
On the predictive modelling of machined surface topography in abrasive air jet polishing of quartz glass
摘要： Abrasive Air Jet Polishing (AAJP) process can be considered as one of the most promising ultra-high-precision finishing methods of quartz glass products due to the superior machined surface integrity, and the high machining feasibility for free-form surfaces. Although many academic and engineering efforts have been paid so far to AAJP process from the theoretical, numerical and experimental aspects, most of the available studies have considered neither (i) the stochastic nature of the abrasive sizes nor (ii) the elastic springback after the impacting abrasives bounced back from the workpiece surface. To fill this gap, this paper proposes the predictive model of the machined surface topography in the AAJP process of quartz glass. A series of experimental trials are performed as well which to a large extent proved the model feasibility and accuracy, and, more importantly, the necessity to consider the normally-distributed abrasive sizes, the stochastic abrasive distribution within the spray airflow, and the elastic workpiece deformation recovery after the AAJP process. Both the experimental and theoretical results also conclude that the small-sized abrasives and the low jet airflow pressure were more effective to achieve the smooth surfaces. The proposed model in this work is expected to be not only helpful to provide the theoretical foundation to study more in-depth mechanism of the AAJP process of brittle materials, but also meaningful to guide the industrial manufacturing in terms of machining parameter optimisation and machined surface quality prediction.
关键词： Elastic springback,Stochastic abrasive size,Plastic deformation,Machined surface topography,Abrasive air jet polishing
更新于2025-09-23 15:22:29
-
A poly (vinyl butyral)/graphene oxide composite with NIR light-induced shape memory effect and solid-state plasticity
摘要： A NIR light-induced shape memory composite with light-induced plasticity was prepared by incorporating graphene oxide (GO) into cross-linked poly (vinyl butyral) (PVB). The cross-linked reaction between PVB and aromatic diisocyanate not only endowed the composites with excellent shape memory properties, but also offered the performance of solid-state plasticity due to the formation of carbamate bonds. The photo-responsive performance was introduced to the system by doping GO, a conventional photothermal reagent, resulting in excellent NIR light-induced shape memory properties and light-induced plasticity. According to the stress relaxation tests, the solid-state plasticity of composites could be regulated by the cross-linked density, GO, catalyst dosage and temperature. Moreover, the composites can be repeatedly programmed to a new permanent shape via a light-induced plasticity process, which still exhibited excellent light-induced shape memory properties even after 5 cycles of reconfiguration. The results demonstrate the promising prospect of these composites as actuator elements for applications in self-deployment devices and soft robotic.
关键词： Smart materials,Functional composites,Shape memory polymers,Polymer-matrix composites (PMCs),Plastic deformation
更新于2025-09-23 15:21:21
-
Impact of interfaces on the radiation response and underlying defect recovery mechanisms in nanostructured Cu-Fe-Ag
摘要： Newest developments in nuclear fission and fusion technology as well as planned long-distance space missions demand novel materials to withstand harsh, irradiative environments. Radiation-induced hardening and embrittlement are a concern that can lead to failure of materials deployed in these applications. Here the underlying mechanisms are accommodation and clustering of lattice defects created by the incident radiation particles. Interfaces, such as free surfaces, phase and grain boundaries, are known for trapping and annihilating defects and therefore preventing these radiation-induced defects from forming clusters. In this work, differently structured nanocomposite materials based on Cu-Fe-Ag were fabricated using a novel solid-state route, combining severe plastic deformation with thermal and electrochemical treatments. The influence of different interface types and spacings on radiation effects in these materials was investigated using nanoindentation. Interface-rich bulk nanocomposites showed a slight decrease in hardness after irradiation, whereas the properties of a nanoporous material remain mostly unchanged. An explanation for this different material behavior and its link to recovery mechanisms at interfaces is attempted in this work, paving a concept towards radiation resistant materials.
关键词： radiation resistant materials,severe plastic deformation,defect-interface interactions,nanostructured materials,nanoindentation
更新于2025-09-23 15:21:01
-
Evaluation of large plastic deformation for metals by a non-contacting technique using digital image correlation with laser speckles
摘要： The full-field deformation characterizations of a metal undergoing large plastic strains are difficult to be obtained from the conventional true stress-strain curves. In this study, we proposed using a simple non-contacting technique, digital image correlation (DIC) with laser speckles, to evaluate large plastic deformations of metals, especially for thin metal foils and for the forming at high temperatures. The feasibility and accuracy of this DIC technique were confirmed by conducting uniaxial tensile tests using different materials. As results, the measured strains indicated a good accuracy with an error range of 6% in measuring the large plastic deformation at room temperature and 10% in measuring a large strain up to 0.6 at a high temperature of 400 °C. The strain distribution measured by DIC with laser speckles and with artificial speckles showed good agreement, confirming the feasibility of this DIC technique for measuring large plastic deformations. By using this technique, the evolution of plastic zone was successfully investigated for thin metal sheets with a thickness of 0.5 mm. Furthermore, the strain fields involving localizations of 50 μm thick metal foils forming at room temperature and a large plastic deformation of metal tubes forming at 400 °C were evaluated qualitatively and quantitatively.
关键词： Large plastic deformation,Digital image correlation,Non-contacting,Laser speckle,Metal
更新于2025-09-23 15:21:01
-
Tailored Nanopatterning by Controlled Continuous Nanoinscribing with Tunable Shape, Depth, and Dimension
摘要： We present that the tailored nanopatterning with tunable shape, depth, and dimension for diverse application-specific designs can be realized by utilizing controlled dynamic nanoinscribing (DNI), which can generate bur-free plastic deformation on various flexible substrates via continuous mechanical inscription of a small sliced edge of a nanopatterned mold in a compact and vacuum-free system. Systematic controlling of prime DNI processing parameters including inscribing force, temperature, and substrate feed rate can determine the nanopattern depths and their specific profiles from rounded to angular shapes as a summation of the force-driven plastic deformation and heat-driven thermal deformation. More complex nanopatterns with gradient depths and/or multidimensional profiles can also be readily created by modulating the horizontal mold edge alignment and/or combining sequential DNI strokes, which otherwise demand laborious and costly procedures. Many practical user-specific applications may benefit from this study by tailor-making the desired nanopattern structures within desired areas, including precision machine and optics components, transparent electronics and photonics, flexible sensors, and reattachable and wearable devices. We demonstrate one vivid example in which the light diffusion direction of a light-emitting diode can be tuned by application of specifically designed DNI nanopatterns.
关键词： viscoelasticity,tailored nanopattern,nanoinscribing,extrusion,light diffusion,plastic deformation,tunable profile
更新于2025-09-19 17:13:59
-
The formation mechanism of globally biaxial strain in He <sup>+</sup> implanted silicon-on-insulator wafer based on the plastic deformation and smooth sliding of buried SiO <sub/>2</sub> film
摘要： In this paper, we proposed an approach to obtain a globally biaxially strained silicon-on-insulator (SOI) wafer, and the strain mechanism was discussed. By this process, both biaxially tensile and compressive strained SOI (sSOI) can be obtained. The strain introduced into the SOI layer is mainly contributed by the plastic deformation of the buried SiO2 film caused by annealing with the deposition of a high-stress SiN film. Furthermore, He+ implantation at the interface between SiO2 and the substrate Si layer is confirmed to effectively enhance the strain by the sliding of the buried SiO2 at the SiO2-substrate Si interface. Raman spectroscopy shows that the strain of the He+ implanted sSOI has a significant enhancement of more than 300% compared with the unimplanted sSOI.
关键词： silicon-on-insulator,biaxial strain,plastic deformation,He implantation,SiO2 film
更新于2025-09-09 09:28:46