نشریه فرآیندهای نوین در مهندسی مواد
پیاپی 67 (زمستان 1402)

One of the most common orthopedic clinic referrals is direct and indirect traumas to the knee that lead to anterior cruciate ligament rupture. The use of titanium implants is one of the ways to treat and reconstruct the cruciate ligament, which has limitations, including the release of toxic ions such as aluminum and vanadium from the titanium alloy. In the present study, the polyether ether ketone (PEEK) implant was fabricated using a CNC machine. Then the surface of the implant was coated with strontium oxide (SrO) by dip spin coating method in two temperature conditions, including ambient temperature and 70 ℃ to produce a radiopaque polymer. After coating, the wear and surface properties of the implant were evaluated. The surface morphology, microstructure, and distribution of elements on the implant surface were evaluated by scanning electron microscope (SEM), X-Ray Diffraction (XRD), X-ray energy diffraction spectroscopy(EDS), and MAP analysis, respectively. The radiographic images indicated the good radiopacity level of the SrO-coated PEEK implant. The amount of weight loss for the PEEK implant and the SrO-coated PEEK implant was 0.0006 g and 0.0004 g in 1500 cycles, respectively. Good wear resistance was observed in two cycles of 500 and 1500 for the pores and surface of the SrO-coated PEEK implant. The results of the cell culture and live/dead staining showed 98% growth and proliferation of cells on the SrO-coated PEEK implant. Therefore, the findings of this study demonstrated that the SrO-coated PEEK implant can be used as a suitable alternative for the Endobutton.

In the present study, the Bismuth doped GdF3 nanoparticles were synthesized via the hydrothermal method and the effect of temperature, time and NH4F concentration was investigated. The Poly Ethylene Glycol was used as the surfactant. The phases characterization was inducted via XRD, FE-SEM and EDS techniques. The in vitro investigation of the samples as the contast agents were performed using MR and CT imaging. the sample synthesized at 180 oC,, 6 hours and the NH4F concentration twice the Stoichiometric concentration that had the semi spherical structure with mean size lower than 100 nm was the suitable sample and the in vitro studies show that the particles act as an excellent CT contrast agent and also as an effective MRI contrast agent at concentrations between 22.5 and 180 mM. Briefly, The use of Bismuth dopant ant GdF3 nanoparticles was successfully performed and The particles can used as the potential MRI-CT contrast agents.

This research, involved dynamic optimization of process parameters on the porosity and tensile strength of AA1050/SiC aluminum composite wires produced by friction stir extrusion (FSE) was carried out. In this regard, SiC ceramic particles reinforced AA1050 composite samples were produced using the FSE process. Also, response surface methodology (RSM) was used to design of experiment. The rotational speed of the punch, extrusion force, and reinforcement percentage weight were determined as input variables of the process. The porosity and tensile strength of produced composite samples were determined as response variables. Analysis of variance (ANOVA) and regression analysis were used to analyze the obtained data. The results showed that rotational speed, extrusion force with second-order effects, and reinforcement percentage with linear effects were effective on the tensile strength and porosity of composite samples. Also, the optimization of FSE process parameters to reach the minimum percentage of porosity and maximum tensile strength was performed using the desirability method. Finally, the optimization results were evaluated based on the validation test. Also, by achieving the maximum value of the desirability function (0.9852), the optimal conditions of process input variables were a rotational speed of 787 rpm, an extrusion force of 11.7 kN, and a reinforcement percentage of 3.86% to simultaneously achieve the maximum ultimate tensile strength (155.4 MPa) and minimum porosity percentage (0.45%). Also, the values obtained from the optimization were compared with the experimental values and the accuracy of the results in tensile strength and porosity were confirmed with 2.57% and 6.78% errors, respectively.

The purpose of this paper is to analyze the effect of molybdenum and cobalt additives on the dielectric, ferroelectric and piezoelectric properties of PZT5piezoceramic material By adding molybdenum and cobalt in the location of zirconate and titanate, in the range of (0-2) percent.For this purpose, the powders were first prepared with a wet chemical method. then They were calcined for 2 hours at 850 ° C. The structural properties of the compounds were investigated using the X-ray diffraction (XRD) method to confirm the formation of single phase compounds (with perovskite structure) at room temperature. The Microstructural analysis of the surface of the sintered discs by scanning electron microscopy (SEM) shows that there is a significant change in grain size with increasing molybdenum and cobalt. Detailed studies of the dielectric properties of PZT In the samples made and tested show measurable change in the piezoelectric charge coefficient D33(Up to 84 ℅ reduction), electromechanical coupling coefficient Keff(Up to 78 ℅ reduction) , resonant frequency Fr(Up to 25 ℅ increase) and mechanical quality factor Qm (Up to 110 ℅ increase).

In the present study, the effect of thermal treatment on the corrosion behavior and microstructure changes of two-layer stainless-304-Cu sheet steel sheets after the explosive welding process has been investigated. Explosive welding has been done in parallel with an explosive layer of 46 and 63 µm and a stop distance of 2-3 mm. After explosive welding, the heat treatment process was carried out at 350 and 450 ° C for 8 and 16 hours. Explosive welding with an explosive load and variable stop distance. From the results of the electrochemical impedance test, it can be seen that the n number in the heat treatment sample at 350 ° C and 8 hours is less than the heat treatment sample at 450 ° C and 8 hours, and as a result, the corrosion current in the heat treatment sample The temperature is 350 ° C and the time is 8 hours, which reduces the load transfer resistance. By comparing the heat treatment samples at 350 ° C and 8 hours and the heat treatment at 450 ° C and the time of 8 hours with varying aniline temperature, the annealing time is constant and the heat treatment sample at 450 ° C and time 8 The hour with more annealing temperature has a value of n (0.80), followed by heat treatment at 350 ° C and 8 hours (n = 0.66), due to annealing temperature and reduced energy storage In the chapter.

This research investigated the effect of reducing agent type on the synthesis behavior and microstructure of Ni-Cr-Mo alloy, which was synthesized by microwave-assisted self-propagation high-temperature. For this purpose, powder mixtures with the same amount of NiO, MoO3, and Cr2O3 as precursors and different ratios of aluminum to silicon as reductants were prepared. The mixtures were homogenized, compacted to a 20 mm diameter disk, and synthesized by a microwave oven. Results show that although the adiabatic temperature in the silico-thermic sample exceeded the merzhanov criteria, the synthesizing did not occur due to Si high-temperature melting point. The maximum recovery efficiency of Ni and Mo was observed in the Al50 with 92% and 96%, respectively. But, the recovery efficiency of Cr in this sample was 36%, which is very low. Using excess Al in 1.1 and 1.2 times more than the stoichiometric ratio in the Al50ex1.1 and Al50ex1.2 leads to the recovery efficiency of Cr rising 25% and reaching 45%. The presence of residual Si in the produced alloys caused to formation Mo2Ni3Si phase, which is a Mo and Si reach the compound. Microstructural investigation shows residual Si content, and Mo2Ni3Si phase percent were increased by adding excess Al in the initial mixtures. Also, the Mo2Ni3Si proeutectic phase has petaloid morphology. Although the Mo2Ni3Si phase is not formed in the Al100 sample, the severe segregation of Mo led to a continuous network of semi-dual phases in the dendrite boundary.