Masoud Kasiri-Asgarani

In this research, copper/silver-silicon carbide Cu-Ag-SiC composite was prepared by the friction stir processing (FSP). For this purpose, nanometer and micrometer SiC particles were used as reinforcing particles. In order to evaluate the microstructural properties, X-ray diffraction (XRD) analysis, scanning electron microscope and optical microscope were employed. Evaluation of mechanical ...

In this research, dissimilar joining of biodegradable AZ31 alloy to Ti-6Al-4V titanium alloy by rotary friction welding method was investigated with aim of preparation of pin or screw for orthopedic applications. optical and scanning electron microscope (sem) were used to investigate the microstructure, x-ray diffraction was conducted for phase analysis, ...

The influence of Ca on the microstructure characterization, mechanical performance, corrosion behavior, and cytocompatibility of Mg-Zn-Al magnesium alloy was studied. Mg-Zn-Al and Mg-Zn-Al-xCa alloys were evaluated as cast. Scanning electron microscopy demonstrated that the microstructure of the Ca-containing alloys was substantially finer and more uniform than the standard Mg-Zn-Al alloy. Hardness and compressive strength tests revealed that the addition of Ca boosted hardness and compressive strength while decreasing ductility. The corrosion resistance of the investigated alloys was enhanced initially but dropped as the Ca concentration increased. The corrosion resistance performance of Mg-Zn-Al-0.5Ca alloy was the best, with a corrosion rate of 3.7 mm/y due to the specific microstructure and dense products related to the corrosion on the sample surface. Cytotoxicity experiments showed that Mg-based alloys with a low Ca content have higher cell viability than Mg-Zn-Al and Mg-based alloys with a high Ca concentration, indicating improved biocompatibility. As a result, Mg-Zn-Al-0.5Ca alloys can be termed alloys with superior corrosion resistance and great mechanical properties that display high corrosion resistance as well as good biocompatibility.

Porous structure, biocompatibility and biodegradability, large surface area, and drug-loading ability are some remarkable properties of zeolite structure, making it a great possible option for bone tissue engineering. Herein, we evaluated the potential application of the ZSM-5 scaffold encapsulated GEN with high porosity structure and significant antibacterial properties. The space holder process has been employed as a new fabrication method with interconnected pores and suitable mechanical properties. In this study, for the first time, ZSM-5 scaffolds with GEN drug-loading were fabricated with the space holder method. The results showed excellent open porosity in the range of 70–78% for different GEN concentrations and appropriate mechanical properties. Apatite formation on the scaffold surface was determined with Simulation body fluid (SBF), and a new bone-like apatite layer shaping on all samples confirmed the in vitro bioactivity of ZSM-5-GEN scaffolds. Also, antibacterial properties were investigated against both gram-positive and gram-negative bacteria. The incorporation of various amounts of GEN increased the inhibition zone from 24 to 28 (for E. coli) and 26 to 37 (for S. aureus). In the culture with MG63 cells, great cell viability and high cell proliferation after 7 days of culture were determined.

Phase transformations and the melting range of the interlayer BNi-3 were investigated by differential scanning calorimetry, which showed three stages of crystallization during heating. There were three exothermic peaks that indicated crystallization in the solid state. The cobalt-based X-45 and FSX-414 superalloys were bonded with interlayer BNi-3 at a constant holding time of 10 min with bonding temperatures of 1010, 1050, 1100, and 1150 °C using a vacuum diffusion brazing process. Examination of microstructural changes in the base metals with light microscopy and scanning electron microscopy coupled with X-ray spectroscopy based on the energy distribution showed that increasing temperature caused a solidification mode, such that the bonding centerline at 1010 °C/10 min included a γ-solid solution, Ni₃B, Ni₆Si₂B, and Ni₃Si. The athermally solidified zone of the transient liquid phase (TLP)-bonded sample at 1050 °C/10 min involved a γ-solid solution, Ni₃B, CrB, Ni₆Si₂B, and Ni₃Si. Finally, isothermal solidification was completed within 10 min at 1150 °C. The diffusion-affected zones on both sides had three distinct zones: a coarse block precipitation zone, a fine and needle-like mixed-precipitation zone, and a needle-like precipitation zone. By increasing the bonding temperature, the diffusion-affected zone became wider and led to dissolution.

In the current paper, the role of change in strain routes was investigated, along with the cold rolling of copper metal. Four different strain routes including, (a) unidirectional rolling, (b) reverse rolling, (C) two-stage cross-rolling, and (d) multi-stage cross-rolling, were utilized to investigate the effect of strain routes change on microstructure, texture evolution, and anisotropy. Tensile strength in the unidirectional rolling sample compared to the cross-rolling sample decreased in the direction of initial rolling from 364 Mpa to 340 Mpa, in the direction of 45˚ to the initial rolling from 359 Mpa to 347 Mpa, and in the direction of perpendicular to the initial rolling from 371 Mpa to 360 Mpa. Texture intensity also decreased from 1413 in the unidirectional rolling sample to 992 in the cross-rolled sample. The results demonstrated that by rolling in different routes, the cross-rolling has led to a more homogeneous microstructure, less anisotropy, and weaker texture.