Journal of Environmental Friendly Materials
Volume:6 Issue: 1, Winter-Spring 2022

SG Cast Iron can be utilized advantageously as working materials in a number of devices which can contribute significantly to an environmentally clean energy technology. In this investigation microstructure and mechanical  properties of ferritic-pearlitic spheroidal graphite (SG) cast iron is improve by continuous heat treatment and addition alloying of  trace amount of  tin has been study. Two standard Y-block was designed by in-mold process. Calculations and simulation were accomplished before molding by the Sutcast software. In each experiment, different chemical analysis were applied. The cooling curve of solidification was recorded by the datalogger with labview software and using S-thermocouple (Pt-Rh) attached into the mold. Then Y-block was shakeout from molds and cooled in the air standard specimen were machined for doing mechanical and metallographic exams. The metallographic exams has been indicated that with increasing the rate of shakeout time, the percentage of pearlite in microstructure has been increased. The mechanical test illustrated that with increase the rate of shakeout time, hardness and  tensile strength have been increased, although the percentage of elongation and impact energy have been diminished

Joining of dissimilar metals is one of the most important requirements of different industries. The joining of alloy and plain carbon steels is typically involved in the manufacturing process, and this is because in this case, the cost required for the raw materials is reduced. On the other hand, in the joining of dissimilar metals and alloys, due to their different chemical composition, the strength and quality of the joining joint is largely dependent on the parameters involved in the process. Steel grades 1.7225 (MO40) and St-37 are used in various industries. Due to the conditions, the bond strength of the above steel grades is very important. Therefore, the aim of this study was to investigate the effect of preheating time and temperature parameters on the mechanical properties of the bond formed between the alloy (MO40) 1.7225 and St-37 steel. Studies have shown that among the various parameters, duration and preheating temperature are of great importance in increasing the service life of these parts in the welded state, but so far no detailed study on the duration and The proper preheating temperature for the welding process of steels (MO40) 1.7225 and St-37 is not provided and usually the operating efficiency of these parts is low in severe stress conditions and these parts fail in the welded place.

Nickel-iron alloy coatings with different amounts of ferrous sulfate in plating bath on steel substrate under turbulence 250 rpm and current density 2.5 A d-1m-2 were created. the amount of ferrous sulfate added to the plating bath varied from 20 g l-1 to 80 g l-1. EDX test was taken from each sample. the amount of iron that precipitated from each plating solution in the alloy coating was obtained. it was observed that for the values ​​of 20 g l-1, 40 g l-1, 60 g l-1, 80 g l-1 iron sulfates 21.29(wt.%), 43.35(wt.%), 51.19(wt.%), 58.8(wt.%) iron were deposited in the alloy coating, respectively. According to the SEM photos obtained from the samples, it was observed that only the sample contains 20 g l-1 ferrous sulfates in the plating bath without cracks and increasing the amount of ferrous sulfate in the plating bath leads to an increase in internal stresses in the coating, which is the main reason creating cracks. Finally, the hardness of the coatings was obtained, which was the highest hardness for the 20 g l-1 sample.

In this paper, advanced manufacturing and eco-friendly welding between AISI 409 finned to high pressure T22 boiler tube produced by "High-frequency resistance welding (HFRW)" process has been studied. The current development in the power generation industry is HFRW clean energy contributes to the resolution of the greenhouse effect. HFRW technology was implemented on actual samples by changing multiple parameters. Meanwhile metallography of weld bond, tensile strength and hardness tests were performed on several sections of the samples according to international standard finned tube.  The diffusion zone indicating the schematic of weld width and weld depth of finned tube observed under the scanning electron microscopy (SEM) which is used for analyses width are that the weld width must be ≥ 90% of fin thickness which can be calculated at the weld interface, with applying optimum welding parameters. Moreover, as the pitch and fin thickness are reduced, the output transfer surface treatment in final process diminished. Hence, the parametric optimization HFRW and the higher quality of finned tube welding bond is revealed by the best conditions of fin pitch.

In recent years, composites have been used to reduce the overall weight of the structure and reduce the consumption of fossil fuels in aircraft due to their light weight property. The purpose of this study is to investigate the interlayer stresses created in composite layers due to the effect of free edges. In fact, in this study, the distribution of stresses affected by free edges (interlayer stresses) that create force and torque in the direction of thickness is investigated. For this purpose, the changes of the mentioned stresses with the help of numerical modeling for multilayer composite by finite element method are investigated by Abacus software and the environmental effects of composite materials are also discussed. Finally, the effect of different layers on this phenomenon in terms of thickness and width of several composite layers under axial tensile load will be investigated. As a result, on one hand the extended usage of green materials like composites can potentially reduce the previous heavy metallic structures which use more fuel and have much more environmental side effects, and on another hand some stress analytical results such as symmetrically distribution of , asymmetrically distribution of  across the width of multilayer and other discoveries for angle-ply and quasi-isotropic multilayers due to the effect of free edge are gained.

With the expansion of studies and research to recognize the mouth's biocompatibility properties, the components and types of implants have been examined in terms of different surfaces with respect to one another. The bone around the implant plays a crucial role in supporting and maintaining the stability of the implant after implantation in the gums, and its gradual loss will reduce the biocompatibility and, ultimately, the strength of the bond between the implant fixture surface and the gingival bone. In this study, the 3A implant characteristics have been investigated from the perspective of hydrophilicity, biocompatibility, and osseointegration of this implant's surface. So that the viability of the noted fixture’s titanium surface, when the hydrophilicity has been established in it, should be examined with the time when it lacks the hydrophilicity. Finally, it was found that the adsorption rate of the implant’s titanium surface to the gingival bone decreased from about 8 weeks to about 4 weeks, when the implant surface was hydrophilic compared to the time it lacked this property. The results also show that with the increase of hydrophilicity in the implant surface treatment method, the improvement of surface treatment in the first 2 to 4 weeks after implant placement has grown and gained more speed. This result indicates an acceleration in the process of adaptation of the 3A implant’s titanium surface when it has biocompatibility. The SLActive surface treatment method's high success rate has led to a success rate of 96.8%.

In this research, dissimilar laser spot welding of the Ti-6Al-4V and AISI 304 (stainless steel) was investigated. The joining of 0.7 and 0.5 mm thickness plates with using a copper interlayer of 0.2 and 0.3 mm in thickness was performed by LSW. A 400-W Nd: YAG laser pulse welding machine was used to obtain coaxial spot welds of 4 mm in diameter with circular technique. Visual inspection and metallographic examination were used for all samples. If no crack was identified, micro-Vickers hardness test, tensile test, and scanning electron microscopy (SEM) were performed on the samples. The result indicated that with a copper interlayer and 10.7 J heat input on peak power of 1.5 kW, welding frequency 15 Hz, and welding time of 7 ms, leading to an ultimate strength of 160 MPa.  In addition the result indicated that applying the circular technique by creating adjacent spot welds can produce a good joint.

Due to good biocompatibility, corrosion and mechanical properties, magnesium (Mg) is considered promising degradable material for orthopedic applications. In this work, Mg-Zn alloy scaffolds were produced via powder metallurgy method. The microstructure, composition, in vitro corrosion and mechanical properties of magnesium-zinc alloy scaffolds were investigated. The X-ray diffraction (XRD) results indicated the formed nano precipitates consist of MgZn and MgZn2 intermetallics that dispersed in αMg. The scanning electron microscopy (SEM) images proved that Mg-Zn intermetallics nano precipitates with round morphology and size of 20–50 nm are homogenously dispersed in the αMg matrix. The results showed that the addition of Zn element increases the compressive strength, Young,s modulus and hardness. Also, Mg-(x)Zn alloy scaffolds produced, improved the in vitro anti-corrosion property of the αMg. The best unti-corrosion property is obtained with 3% Zn and further increase of Zn content up 4% deteriorates the corrosion property. All the results suggest that the Mg-Zn alloy scaffolds have the potential to serve as degradable implants for bone substitute applications.