فهرست مطالب

Environmental Friendly Materials - Volume:5 Issue: 1, Winter-Spring 2021

Journal of Environmental Friendly Materials
Volume:5 Issue: 1, Winter-Spring 2021

  • تاریخ انتشار: 1400/03/29
  • تعداد عناوین: 11
|
  • Page 0
  • M. Shahverdi, B .Karbakhsh Ravari* Pages 1-5

    Dual-phase steels are a new class of low-strength alloy steels consisting mainly of ferrite and martensite phases. Dual-phase steels due to their special microstructure represent good mechanical properties and abrasion resistance. In this study, ST52 steel was selected as the prototype specimen because this type of steel after converting to the dual- phase steel will be used in automotive industry. After preparing some specimens of this steel, normalizing treatment was done on them. In order to achievement of dual-phase steel structure and evaluate the different tempering conditions, intercritical annealing was performed at 750 °C and 850 °C for 30 minutes on the specimens. Then tempering was carried out on specimens at 300 °C and 600 °C for one and two hours, respectively. The evaluation of microstructure and mechanical properties, revealed that with increment of the temperature during intercritical annealing, the volume fraction of martensite increases and with increment of the tempering temperature, the volume fraction of martensite decreases. Reducing the amount of martensite phase in most specimens caused to reduce the hardness and tensile strength, but the percentage of elongation increased. Also, increment of the tempering time same as tempering temperature had a similar effect on mechanical properties, while the rate of changes was more than the tempering time. Also, the obtained results showed that the highest hardness (450 Vikers) was related to specimen which intercritical treatment and tempering was performed at 850 °C and 300 °C for one hour, respectively. Additionally, this specimen revealed a highest amount of yield strength (1153 MPa) and a tensile strength (1199 MPa).

    Keywords: Dual Phase Steel, ST52, Martensite volume fraction, Tempering, Hardness, Tensile strength
  • Z. S .Seyedraoufi *, M .Samiee, F .Abdi Pages 7-11

    In this research, the effect of cooling rate on the microstructure, hardness and impact energy of a plastic injection mold made of X210Cr12 steel wasinvestigated. The microstructural studies showed that with increasing cooling rate, the amount of residual austenite (Ar) decreases until it is completely removed.Statistical analysis showed that the size and volume fraction of chromium stabilized with block carbides decreases with increasing cooling rate. As the cooling rate increased, bainites were observed in the microstructure. The hardness decreased via increasing the cooling rate and austenitization time due to the reduced interaction of carbides with dislocations. Martensitic structure prevented a significant reduction in hardness. These factors increased the toughness of the X210Cr12 and led to the ductile failure. Cryogenic treatment modified the structure via distribution of fine carbides into the stable lath martensite. With optimizing the hardness and toughness to withstand the impact of the die, toughness increased to 125 j and hardness decreased to 624 H.V.

    Keywords: X210Cr12 Steel, Cryogenic, Toughness, Microstructure, Hardness
  • S .Ebadi*, K. Shahbazi, E .Anbarzadeh Pages 13-21

    Today, many industries, including the aerospace industry, have been influenced by materials technology development. Aircraft wing structures are generally designed using pure aluminum. Still, in recent years, due to their light weight, composites are used to reduce the overall weight of the structure and lower the consumption of fossil fuels in an aircraft. In this study, the design and analysis of aluminum and composite aircraft wings were done using ANSYS software and are compared. The results show that by using the composite wing instead of the aluminum one, fuel consumption was reduced, bringing positive effects on environmental impacts. According to the results, a 37% reduction in the weight of the composite structure compared to that of aluminum leads to increased aerodynamic efficiency, improved wing performance, reduced fuel consumption and emissions, positive environmental impacts, and reduced construction costs. This is due to the unique properties of composite materials, such as the good power to air ratio and their high flexibility.

    Keywords: Aircraft Wing Design, Composite Structure, Aluminum Structure, Aerodynamic Forces, Environmental impacts
  • M. Ghanbari Haghighi*, P. Parsi, Z. S.Seyedraoufi Pages 23-27

    In the anodizing process of active materials such as titanium, various parameters such as pH, temperature, applied voltage and time, electrolyte composition, etc. affect the formation of the oxide layer during anodising process. In this study, commercial pure titanium as substrate was used to evaluate the effect of voltage and anodizing process on titanium oxide (TiO2). Nanotubes obtained in 1% HF electrolyte from 10 to 30 volts at 60 to 120 minutes. According to field emission scanning electron microscopy studies, nanotube structure of titanium oxide was observed and the diameter and length of nanotubes increase with increasing anode process voltage, and nanotubes become non-uniform and irregular with increasing anode process voltage. Uniform nanotubes with a size of 27 to 32 nm were obtained at a voltage of 10 volts for 60 and 120 minutes. And by increasing the voltage of the anodizing process to 30 volts, a porous structure is formed

    Keywords: Nanotube, Titanium Oxide, anodizing, Porosity
  • R .Bagheri *, S. M .Hosseini Pages 29-34

    In this paper, a theoretical study of the behavior of multiple moving cracks in a non-homogeneous orthotropic plane under anti-plate deformation is presented. Material properties of the functionally graded (FG) orthotropic plane are assumed to vary exponentially in the y-direction. First, the distributed dislocation method is used to perform stress analysis, and the Galilean transformation is used to express the wave equations in terms of the coordinates attached to the moving crack. Then, the solution of the moving screw dislocation in the non-homogeneous orthotropic plane is obtained using the Fourier transform and shows that the stress components have the familiar Cauchy singularity at the location of dislocation. The solution is employed to derive integral equations for a non-homogeneous orthotropic plane weakened by multiple moving cracks. Numerical calculations are performed to show the effects of material properties and the cracks propagating velocity on the dynamic stress intensity factors of crack tips

    Keywords: Dislocation Method, Non-homogeneous material, Multiple Cracks, Dynamic Stress Intensity Factor
  • S. M. J .Hoseini, H. Ghayour, A. S.Golazani, M. K .Asgarani, I .Ebrahimzadeh Pages 35-46

    Spinning is one of the novel and unique processes in metal forming for the production of cylindrical and conical thin-walled parts with precise tolerances, good surface smoothness and suitable mechanical properties. This process includes conventional spinning, shear forming and flow forming. Metallurgical investigation is great importance in this process. The microstructure obtained from the spinning specimens, especially the shear forming and flow-forming, shows that the grains and the impurity particles are elongated in the direction of the main axis and are also stretched in the circumferential direction. This change in grain size on the roller side was larger than on the mandrel side. Fragmentation of coarse and brittle particles has also been observed. Also, due to the amount of strain and forces applied, the grain size decreases and as a result, the strength increases. The texture of the spinning parts has also changed. As the thickness decreases, the orientation of the grains and textures increases and the large angle boundaries increase

    Keywords: Spinning, Shear Forming, Flow Forming, Microstructure, texture
  • R. Hedayatnejad, H. Sabet*, S. Rahmati, A. Salemi Golezani Pages 47-58

    Additive manufacturing (AM) is a general name used for production methods which have the capabilities of producing components directly from 3D computer aided design (CAD) data by adding material layer-by-layer until a final component is achieved. Included here are powder bed technologies, laminated object manufacturing and deposition technologies. These technologies are presently used for various applications in engineering industry as well as other areas of society, such as medicine, aerospace, architecture, cartography, entertainment. Laser metal deposition (LMD) using powder as an additive is an AM process which uses a multi-axis computer numerical control (CNC) machine to guide the laser beam and powder nozzle over the deposition surface. The component is built by depositing adjacent beads layer by layer until the component is completed. LMD has lately gained attention as a manufacturing method which can add features to semi-finished components or as a repair method. LMD introduce a low heat input compared to arc welding methods and is therefore well suited in applications where a low heat input is of an essence. For instance, in repair of sensitive parts where too much heating compromises the integrity of the part. It has been found that the most influential process parameters are the laser power density, scanning speed, powder feeding rate and powder standoff distance and that these parameters has a significant effect on the characteristics of the material such as microstructure

    Keywords: Additive Manufacturing (AM), Laser Metal Deposition (LMD), Process parameters, Power Density
  • H .Bakhtiari *, M .Abaei, M. R. Rahimipour, M .Farvizi, M. J .Eshraghi Pages 59-68

    Quasicrystals are structures that are both regular and non-periodic. In quasicrystals, there is an iterative rule in the arrangement of atoms, along with abnormal rotational symmetry for crystals, that is, they form patterns that fill space but have no transfer symmetry. These structures are generally made of alloys of aluminum, copper, nickel, magnesium, zinc, zirconium, and titanium. These materials have attracted the attention of many researchers in recent years due to their extraordinary physical and mechanical properties. Due to the extraordinary properties and different production methods, it can be expected that these materials will be used more in different industries in the near future. Therefore, it is very important to study the methods of preparation of these materials. In this article, we first introduce the quasicrystals and their outstanding properties and then examine their common production methods, which include melt spinning, mechanical alloying, coating method, sputtering, physical vapor deposition, and thermal spraying, along with their advantages and disadvantages

    Keywords: Quasicrystal, properties, Production Methods
  • H. Bakhtiari*, M. R. Rahimipour, M .Farvizi, M. R .Khanzadeh Pages 69-76

    Quasicrystals, unlike crystals that contain regular and repetitive patterns, are composed of regular patterns that are not repetitive. Moreover, the symmetry of quasicrystals in crystals is impossible. For example, ordinary crystals can have triple symmetries from the repetition of a triangle or quadruple symmetries from the repetition of a cube. Quasicrystals are a special type of real crystals that are artificially formed only in laboratories, under certain conditions and temperatures, and it is not possible to form them like the earth. Evidence suggests that quasicrystals can form naturally under conditions contrary to astrophysical laws and remain stable for long periods. Quasicrystals are a group of new materials with unique mechanical, physical, and chemical properties. Among the known properties of these materials are low adhesion and friction, high resistance to corrosion, very high hardness, electrical insulation at low temperatures, and light absorption. Quasicrystals are used in non-stick coatings, nanoparticles, hydrogen storage, reinforcing phases in composites, catalysts, thermal insulation, infrared light absorption, and corrosion protection. In this article, we refer to some of the main topics related to quasi-crystal

    Keywords: Quasicrystal, structure, Mechanical, Chemical Properties
  • N. Desai*, P .Bhatt, M. Solanki Pages 77-87

    Energy crisis has been posing a great concern on the exploitation of limited resources and causing dramatic impact on the global economy. With the growing shortage of electricity, a rapid evolution has been observed in the wind power technology as a clean source of renewable energy. Along with considering the strength requirements and considerable forces acting on the blades of wind turbines throughout its operating lifetime, the continued growth of the industry also strengthens the need for gaining critical material knowledge for the wind turbine blades. This gives direct rise to challenges in material selection process, a major area of potential improvement. The focus of this review paper is the need for improved material knowledge, advanced, economic, and environmentally friendly materials for wind turbine blades. Present piece of research attempts to conclude various potential green bio-composites which have an edge over the existing conventional materials for the application of wind turbine blades and could prove to be a remarkable advancement in the field of wind energy. Along with the material selection, detailed insights about property requirements for wind turbine blades, problems encountered in the present-day materials, characteristics for selecting reinforced fibres, material testing, and manufacturing process of wind turbine blades have also been studied

    Keywords: Wind Turbine Blades, Bio-Composites, Natural Fibres, Biodegradable Matrix, Material property, Biodegradability