Including fluorescent nanoparticle probes within injectable gels for remote strain measurements and discrimination between compression and tension

Remote measurement of the deformation ratio and discrimination between tension and compression for injectable gels is demonstrated using photoluminescence and two types of fluorescent probe particles.

Shear Stress-Triggered Deformation of Microparticles in a Tapered Microchannel

We demonstrate that it is possible to produce microparticles with high deformability while maintaining a high effective volume. For significant particle deformation, a particle must have a void region. The void fraction of the particle allows its deformation under shear stress. Owing to the importance of the void fraction in particle deformation, we defined an effective volume index (V*) that indicates the ratio of the particle’s total volume to the volumes of the void and material structures. We chose polyethylene glycol diacrylate (Mn ~ 700) for the fabrication of the microparticles and focused on the design of the particles rather than the intrinsic softness of the material (E). We fabricated microparticles with four distinct shapes: discotic, ring, horseshoe, and spiral, with various effective volume indexes. The microparticles were subjected to shear stress as they were pushed through a tapered microfluidic channel to measure their deformability. The deformation ratio R was introduced as R = 1−Wdeformed/Doriginal to compare the deformability of the microparticles. We measured the deformation ratio by increasing the applied pressure. The spiral-shaped microparticles showed a higher deformation ratio (0.901) than those of the other microparticles at the same effective volume index.

Effect of CU Foam and Ag-Coated Layer on the Microstructure and Mechanical Behavior of Nano-Ag Sintered Joint

Cu foam (Cu-F) and Ag-coated Cu-F were added into nano-Ag paste to obtain Cu-F@nano-Ag composite sintered joint. The microstructure, hardness, and shear behavior of the sintered joints were investigated. Experimental results indicated that the addition of Cu-F and Ag-coated Cu-F suppressed the generation and propagation of cracks at the interface of the sintered joint. As the thickness of the Cu-F increased from 0.1mm to 0.2mm, the deformation ratio of the Cu-F sheet raised from 12 % to 50 %. Thereby, the hardness and bonding strength of the sintered joint was improved due to the microstructural densification. The bonding quality between Cu-F and sintered Ag is enhanced by the Ag-coating treatment. Therefore, the Ag-coated composite joints show higher shear strength than the others.

Prediction of Tensile Strength and Deformation of Diffusion Bonding Joint for Inconel 718 Using Deep Neural Network

Due to the acceptable high-temperature deformation resistance of Inconel 718, its welding parameters such as bonding temperature and pressure are inevitably higher than those of general metals. As a result of the existing punitive processing environment, it is essential to control the deformation of parts while ensuring the bonding performance. In this research, diffusion bonding experiments based on the Taguchi method (TM) are conducted, and the uniaxial tensile strength and deformation ratio of the experimental joints are measured. According to experimental data, a deep neural network (DNN) was trained to characterize the nonlinear relationship between the diffusion bonding process parameters and the diffusion bonding strength and deformation ratio, where the overall correlation coefficient came out to be 0.99913. The double-factors analysis of bonding temperature–bonding pressure based on the prediction results of the DNN shows that the temperature increment of the diffusion bonding of Inconel 718 significantly increases the deformation ratio of the diffusion bonding joints. Therefore, during the multi-objective optimization of the bonding performance and deformation of components, priority should be given to optimizing the bonding pressure and duration only.

System Deformation Behavior of Friction Pair in Fretting Wear

Several criteria for fretting wear behavior evaluation have been established since the proposal and establishment of the fretting loop concept. In this article, system deformation and system deformation ratio were defined. In addition, the fretting running conditions were distinguished from the evolution of system deformation with fretting cycles during fretting wear tests under different applied displacements and loads. In the gross slip regime, the system deformation was independent of the applied displacement and increased as the load increased, whereas in the partial slip regime, the system deformation was independent of the load and increased with the applied displacement. Furthermore, a linear relationship between the system deformation and the applied load in gross slip regime was found for the first time. Based on this linear relationship, the system deformation ratio can forecast the running regime with a given load and displacement. For the titanium alloy fretting pairs studied in this article, the fretting wear was found to run in the gross slip regime if the system deformation ratio was smaller than 0.9. Based on these observations, the system deformation ratio exhibited applicability in assisting the mechanical design of equipment suffering from fretting wear.

The Influence of Temperature and Deformation Ratio on Structure Formation and Physico-Mechanical Properties of Powder Materials

The paper presents the materials on researching the use of current conductor copper waste for getting new functional materials. The changes of maximum deformation ratio, density, microstructure and hardness of powder copper preforms at different temperatures and deformation rates have been studied. The result is that the value of the maximum deformation ratio depends on kinetics of dynamic weakening processes. The change of the microstructure depending on the temperature and deformation ratio has been scrutinized. It has been established that the most fine-grained structure was got at the temperatures of dynamical recovery and recrystallization. The temperature intervals of stamping for manufacturing products by pressing are recommended. On the basis of experimental researches a resource-saving manufacturing method of producing axisymmetric details of high density from powder copper material with the use of maximum deformation ratios has been elaborated.

Effect of microstructure on tensile properties of Ti-17 alloys forged using a 1500-ton forging simulator

Microstructure dependence on mechanical properties were investigated for Ti-17 forged at temperatures between 700 and 850 ˚C with deformation ratio from 33 to 80 %, and solutiontreated at 800˚C for 4 hours and aged at 620 ˚C for 8 hours. The microstructure was observed after solution and aging treatments. The volume fraction and the size of the primary alpha phase was controlled by solution treatment temperature, not forging temperature and deformation ratio. Forging temperature affected the morphology of grain boundary (GB) alpha phase. Deformation ratio affected the grain size and the aspect ratio of the horizontal and vertical grain size of the prior beta phase. The tensile strength was investigated at room temperature, 450, and 600 ˚C. Forging temperature and deformation ratio did not affect the tensile strength because there is no large difference of the volume fraction of the alphaphase. On the other hand, the elongation and the reduction of area increased with increase of the aspect ratio of the prior beta grains; that means, increase of the deformation ratio. Raising of forging temperature also increased elongation and reduction of area due to the film-like GB alphaphase.