Advanced Materials Research Vol. 1052

Abstract: Thiols play key roles in biological systems. They are important parts of many organisms proteins and small molecules, and have an important role in cellular antioxidant systems. In recent years, fluorescent methods for detecting the mercapto compounds have developed rapidly, based on its apparent advantages in sensitivity, specificity and nondestructive imaging. Therefore, the quantitative detection of mercapto biomolecules are very important in biochemical and clinical chemistry. In this review,we summarized the fluorescent probes for thiols according to their unique mechanisms between fluorescent probes and thiols.

Abstract: Punch is a key component in Socket-Spanner extrusion and its shape influence the extrusion molding heavily. Using the FEA software DEFORM, the paper simulated the extrusion process of three kinds of upper and lower extrusion punch combinations which have different shape and studied the influences of the punch shape on metal flowing, Z direction punch load and equivalent stress. By contrasting the simulation data, the best punch shape was chosen. Our results could provide theory evidence for optimization design of Socket-Spanner extrusion punch. It was shown that the tapered bottom punch is the most suitable shape for the socket-spanner extrusion than the flat tapered and the flat one.

Abstract: Pre-stress shot peen forming is a metal forming process widely used in aeronautical industry. The test parts of 7150 Al alloy of different thickness were pre-stress shot peen formed. The deformation rule of those parts was investigated by means of changing the peening coverage. The results show that the radius of curvature of the parts will enhance gradually with increasing of the plate’s thickness. In addition, enhancing peening coverage could raise the deformation in the case of that the thickness and peening parameters are unchanged. Furthermore, the minimum radius of curvature of the 8mm plate after saturation pre-stress shot peen forming could reach 499mm.

Abstract: This article gives an overview of study on injection molding process of thermoplastic polymer SPCs. The thermoplastic polymer Polypropylene (PP) was selected as the experimental materials. Our study proves that advantages of the PP SPCs are friendly recyclability and excellent fire/matrix adhesion. PP SPCs samples had good interfacial compatibility and bonding properties. The one-component SPCs have better interfacial bonding than the multi-component SPCs. Injection molding is the most effective method with a large process window and short cycle time for processing a thermoplastic SPC. Injection molding could be developed to realize PP SPCs production.

Abstract: the effects of turning on the gradients of micro-texture and grain size of Al alloy 7075 processed by turning is studied. Analytical models based on Boussinesq equation and stress/force transformation, predict that the equivalent von-Mises stress penetrate almost 1 mm below the machined surface with a maximum of 1400 MPa. The induced temperature below the surface is and reaches up to 240°C. As a result of deformation below the machined surface, the grains below the surface show a preferred grain shape orientation different from the grains in the central region. The normalized population of (121) plane increases at the machined surface compared to the central part of the sample. Orientation distribution functions reveal that at the central part of the sample, the material is mostly randomly oriented and the closest texture component is the recrystallized texture. On the other hand, the strongest texture attribute at the machined surface is β-fiber torsion. The average grain size shows a 10% decreases moving away from center while below the machined surface there is a 50% increase in the average grain size. This can be due to the grain growth caused by higher temperatures right below the machining tool. The reported results provide a toolset to determine the final properties of the material after machining in addition to providing means to more accurately describing the machining mechanics.

Abstract: The paper studies the optimal parameters of injection molding to avoid the deformation, warping, short shot, and surface defects for the plastic components of Braille display cell. At first the Pro/Engineer parametric software is applied for the entity design and rendering. Then the Mold-Flow software is used for mold flow analysis on the influence of each injection parameters. The results show mold temperature, melt temperature, injection pressure, and filling time are the most influential factors on reducing component deformation. Besides, the L9 orthogonal array of Taguchi method is applied to find out the optimal parameters of injection molding. The deformation, short shot and surface defects of the plastic components in Braille display cell are reduced.

Abstract: This study investigated the process parameters effect on the phase transformation during grinding by experimental validation and correlation analyses. The quantitative material phase link to the kinetics of diffusion-controlled as well as diffusionless transformations in different strain rate and contact zone temperature by examining process parameters is presented. Based upon the mechanical physics-based modeling and prediction for the volume fraction of phase transformation in continuous heating under anisothermal conditions, the correlation between volume fractions of phase in sequential segmented isothermal processes, and grinding process parameters characteristic are developed. In validation of the correlation, a series of maraging steel 250 grinding experiments, XRD measurements, and correlation analyses were pursued. Certain linear correlations between the cutting parameters and the phase transformation were calculated by using the correlation coefficient and the affected degree of cutting parameter, temperature, and strain rate was evaluated by applying partial relation coefficient analysis method. It is practical to alter the part material properties through the phase transformation with process parameters optimal control.

Abstract: The fatigue properties of refill friction stir welding joints of 6082-T6 aluminum alloy were completed based on the optimal process parameters. The expression of the fatigue life prediction were obtained in a certain range. The microstructure and fatigue fracture appearance of welding joints were observed and analyzed. And the microhardness of the joints were tested. The results showed that the fatigue crack initiated from the root of the joints between the lower and upper plate, that is the junction of HAZ and TMAZ, and then propagated to fracture along the boundary between the HAZ and the TMAZ. Strengthening phase which was formed of trace elements significantly affected the fatigue properties of spot welding joints. The fatigue life of spot welding joints along with stress intensity factors decrease showed an increasing trend. Fatigue life of spot welding joints emerge an increasing trend along with decreases of the load.

Abstract: The work presents the possibility of application of inexpensive iron-base powders in the production of sintered diamond tools. It has been shown that ball-milled Fe-Ni-Cu-Sn-C and Fe-Mn-Cu-Sn-C powders can be consolidated to a virtually pore-free condition by hot pressing at 900°C. The as-consolidated materials are characterised by a combination of high hardness, mechanical strength and resistance to abrasion. Their properties can be widely modified by changing the milling time.

Abstract: The main objective of the present work is to characterise the microstructure and mechanical properties of a new iron-base material which has been recently gaining ground in the manufacture of diamond impregnated tools as an economical substitute for cobalt and cobalt alloys. Its density, hardness and yield test properties have been directly compared to those of hot pressed Cobalt Extra Fine (CoEF) powder. It has been shown that the raw iron-663 bronze powder mix can be consolidated to a virtually pore-free condition by hot pressing at 880°C. Although the as-consolidated material is inferior to cobalt, it displays a favourable combination of hardness, yield strength and ductility, and seems to have a great potential for moderate and general purpose applications.