Accuracy of residual stress measurement using the Sin^2 ψ method has become a focus in many applications where residual stress plays a critical role in components, such as aeronautics, railway welding, bearings, gears, etc. Accuracy in residual stress measurement requires consideration of both correctness and uncertainty. In this paper, a self-designed and home-made in-situ tension/compression device is adapted to evaluate the correctness of residual stress measurement in titanium alloy. A calculation method employing multiple convolutions to evaluate the uncertainty of residual stress measurement is presented. Test results show that the X-ray elastic constant is an important parameter impacting the correctness of residual stress measurement. And that the uncertainty of residual stress measurement fluctuates with the surface status of shot peened samples.

In this study, we report on the rational design and facile preparation of a cotton-reduced graphene oxide-silver nanoparticle (cotton-RGO-AgNP) hybrid fiber as an electrode for the building of a flexible fiber-shaped supercapacitor (FSSC). It was adequately characterized and found to possess a well-defined core−shell structure with cotton yarn as a core and a porous RGO-AgNP coating as a shell. Thanks to the unique morphological features and low electrical resistance (only 2.3 Ω·cm⁻¹), it displayed attractive supercapacitive properties. When evaluated in a three-electrode setup, this FSSC electrode delivered the highest linear and volumetric specific capacitance of up to ca. 12.09 mF·cm⁻¹ and ca. 9.67 F·cm⁻³ with a satisfactory rate capability as well as a decent cycling stability. On the other hand, an individual parallel symmetric FSSC cell constructed by this composite fiber fulfilled the largest linear and volumetric specific capacitance of ca. 1.67 mF·cm⁻¹ and ca. 0.67 F·cm⁻³ and offered the maximum energy density, as high as ca. 93.1 μWh·cm⁻³, which outperformed a great number of graphene- and textile yarn-based FSSCs. Impressively, bending deformation brought about quite a limited effect on its electrochemical behaviors and almost no capacitance degradation took place during the consecutive charge/discharge test for over 10,000 cycles. Consequently, these remarkable performances suggest that the currently developed cotton-RGO-AgNP fiber has considerable application potential in flexible, portable and wearable electronics.

Ti(C, N)‐based cermet materials represent the best choice of materials for the manufacturing industry and military products. In this study, we use cubic β‐cobalt(β‐Co) as the binder phase to strengthen constructed cermets. At the same time, to optimize the microstructure, (Ti, W, Mo, Ta) (C, N) powders are added to form two kinds of core‐rim morphologies. Here, β‐cobalt powders with face‐centered cubic structures are obtained by the solid‐phase reaction of high‐energy ball milling. A solid‐phase chemical reaction and a carbothermic reduction‐nitridation method are used to prepare the (Ti, W, Mo, Ta) (C, N) powders. In our process, first we mix the cobalt and (Ti, W, Mo, Ta) (C, N) powders; then we press the powder mixtures into rectangular samples and sinter them in a pressure sintering furnace to obtain Ti(C, N)‐based cermets with two kinds of core‐rim structure, that is, black core/white rim and white core/gray rim. The results show that the new cermets demonstrate excellent toughness and performance.

Tungsten carbide-based (WC-based) cemented carbides are widely recognized as high-performance tool materials. Traditionally, single metals such as cobalt (Co) or nickel (Ni) serve as the binder phase, providing toughness and ... | Find, read and cite all the research you need on Tech Science Press

Cubic phase cobalt (Co), which can be used as a key component for composite materials given its excellent ductility and internal structure, is not easy to obtain at room temperature. In this study, oxalic acid and cobalt nitrate are used as raw materials to synthesize the cobalt oxalate precursor, which has a stable structure with a five-membered chelate ring. Cobalt oxalate microspheres, having a high internal energy content, were prepared by using mechanical solid-state reaction in the presence of a surfactant, which can produce spherical micelles. The thermal decomposition of the precursor was carried out by maintaining it in a nitrogen atmosphere at 450°C for 3 h. At the end of the procedure, 100 nm cubic phase-Co microspheres, stable at room temperature, were obtained. Isothermal and nonisothermal kinetic mechanisms of cobalt grain growth were investigated. The cubic-Co grain growth activation energy, Q, was calculated in this study to be 71.47 kJ/mol. The required reaction temperature was low, making the production process simple and suitable for industrial applications.