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This study is made to obtain controllable and improved microstructural properties of a material obtained by stacking copper wires and then combining them with hot diffusion welding. The mechanical performance of the new approach to obtain a copper billet was assessed and accordingly the diffusion welding parameters were optimized. Samples with a dimension of 60×40×5 mm were produced by stacking. Copper wires with different diameters were stacked in the same direction and welded with hot diffusion welding under 69.5-139-208.5 MPa pressures, for 20-60-90 minutes, at 600 °C. Strength of the bonding was tested by bending and microhardness tests. In addition, the diffusion interface was examined by optical microscope and SEM. The interfacial bond strength after welding increased with temperature, pressure and time. Especially, the increase in diffusion time actuated the formation of common grains in the fusion area by decreasing or completely eliminating the interfaces of the wires. [ABSTRACT FROM AUTHOR]

The present work is focused on the influences of reinforced particles on mechanical, microstructural, and tribological performances of AA7075 hybrid metal–matrix composites (HMMCs). Al2O3 and coconut shell ash (CSA) were reinforced using two-stage stir casting by varying the wt% (0–5) of reinforcement. Microstructural analysis and various phase identifications were examined with the help of scanning electron microscope (SEM) equipped with EDX and optical microscope. Various mechanical testing such as tensile, hardness, 3-point bend test, and tribological behaviors were carried out to know the HMMCs properties. Microstructural images revealed a homogeneous distribution of reinforced particles in the metal–matrix and EDX confirmed the presence of dispersed reinforcements (Al2O3 and CSA) in the HMMCs. It was seen that mechanical properties and tribological behavior have been increased after addition of Al2O3 and CSA reinforced particles whereas slightly decreased in impact strength. Transgranular cleavage facets, micro-void coalescence, dimples, and crack were shown in SEM images of fractured specimens during impact and tensile testing. [ABSTRACT FROM AUTHOR]

Experiments were conducted to investigate the development of an ultrafine grain structure during compression with oscillatory torsion processing of high-purity aluminum (99.9%) with an initial grain size of 75 μm. The samples were processed using different deformation parameters: torsion frequency ( f ) and compression rate ( v ). The samples were examined using a scanning electron microscope equipped with a field emission gun and an electron backscattered diffraction detector. The results suggest that for high-purity aluminum an ultrafine-grained microstructure was obtained after a total effective strain ( ɛ ft ) of 45 in samples deformed at f = 1.6 Hz and v = 0.04 mm/s. A quantitative study of the microstructural parameters showed that the area fraction of the ultrafine grains (<1 μm) ( A 1μm ) was 44%, the fraction of high-angle boundaries was 53%, and the average diameter of the grains was about 600 nm. The yield stress and ultimate tensile stress reached 127 and 137 MPa, respectively, after deformation at a total effective strain of 45. When the total effective strain reached 120, the mechanical strength of the material decreased. This suggests that the decrease in strength is associated with the operation of the recovery mechanism that decreases the boundary volume. [ABSTRACT FROM AUTHOR]

In this paper, we explore the glycosylation conditions (glucomannan content, reaction time, temperature and humidity) to probe the relationship between glycosylation and mechanical properties of soy protein isolate (SPI) film. The mechanical properties were characterized by studying the tensile strength (TS) and elongation at break (EB). Furthermore, degree of glycosylation, free glucomannan content, surface hydrophobicity, sulfhydryl groups content, lysine and arginine content of glycosylation soy protein with different reaction time were investigated to certify the significant effect of glycosylation on mechanical properties of soy protein film. What is more, the comparison of TS and EB, contact angle values and water vapor permeability of glycosylation SPI (GSPI), SPI and mixture of SPI and glucomannan films showed the excellence of GSPI. At the end, the analysis of scanning electron microscope was applied to reveal the effect of glycosylation on the structure of films. These results suggested that glycosylation with glucomannan is an ideal method to enhance the mechanical properties of soy protein isolate film. [ABSTRACT FROM AUTHOR]

A graft copolymer composed of poly (2-hydroxy ethyl acrylate) (PHEA) as branched chains and chlorinated polyethylene (CPE) as backbone, CPE- cg-HEA, was synthesized by in situ chlorinating graft copolymerization (ISCGC). The polymer has special molecular structure with short graft chains and abundant branched points. The mechanical properties of CPE- cg-HEA were studied by tensile testing, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA). The morphologies of tensile fractured surfaces for CPE and CPE- cg-HEA were investigated by scanning electron microscope (SEM). The testing results indicated the mechanical properties of the in situ chlorinating graft copolymers have greatly improved compared with CPE with about the same chlorine content. Particularly, there was a broad plateau on the stress–strain curve of the graft copolymer, which meant a high elastic-like deformation. [ABSTRACT FROM AUTHOR]