• TECHNOLOGIES

    Mechanical properties of parts fabricated with additive manufacturing: A review of mechanical properties of fused filament fabrication parts

    Machines. Technologies. Materials., Vol. 16 (2022), Issue 8, pg(s) 274-279

    Additive Manufacturing (AM) Technologies are in constant development since their emergence in the late 80s. However, standardization is still in its infancy, owing to the numerous changing variables in each process. One of the most common are the material extrusion process, in which thermoplastic is extruded, also known as fused filament fabrication (FFF). The popularity of this process is due to the relatively simple method as well as the relatively good mechanical properties of the fabricated parts. There are numerous research studies evaluating mechanical properties because the FFF process allows for the investigation of many variables and the production of many parts with a wide range of characteristics. But how good are those characteristics in reality, and how good do we need them to be? It all depends on the application for which those parts are required.

  • Electronic properties of carbon nanostructures

    Materials Science. Non-Equilibrium Phase Transformations., Vol. 8 (2022), Issue 1, pg(s) 10-12

    The properties of an array of carbon nanostructures or a material containing its is differ from the properties of individual components. For bulk array of carbon nanostructures it is unknown to what extent the electrons of each layer participate in conductivity, the role of defects is not defined. properties. So, this work presents some answers to these questions.

  • TECHNOLOGIES

    Effect of the forging process in a tool implementing alternating deformation on the structure and mechanical properties of AISI-5140H low-alloy structural steel

    Machines. Technologies. Materials., Vol. 16 (2022), Issue 5, pg(s) 165-166

    The article describes the concept of a new forging method of circular cross-section blanks in a forging tool, the design of which makes it possible to develop significant alternating deformations in the deformable metal. The results of comparative studies of the microstructure and mechanical properties of AISI-5140H low-alloy structural steel, formed in a new forging tool that implements alternating deformation and in flat strikers are presented.

  • TECHNOLOGIES

    Quality assessment of heterogeneous welding joints made by GMAW method

    Machines. Technologies. Materials., Vol. 16 (2022), Issue 5, pg(s) 159-164

    At present, various types of steel grades are used in the production of welded structures and assemblies, resp. combinations of ferrous and non-ferrous metals. In these mutual combinations, it is necessary to know the specifics of weldability of both materials, to choose a suitable welding technology and a suitable filler material. In the experimental part, the quality of heterogeneous welded joints was verified by the GMAW method. A protective gas atmosphere of 82% Ar + 18% CO2 was used for welding (M21 – ISO 14175: 2008). The possibilities of welding and mutual combinations of austenitic stainless steel with structural non-alloy steel, structural alloyed high-strength steel with structural non-alloy steel were assessed. The quality of welds was evaluated using non-destructive and destructive tests in terms of standards: visual test STN EN ISO 17637, capillary penetration test STN EN ISO 22476-12, internal errors were evaluated using radiation tests STN EN ISO 17636-1. The destructive tests used the tensile test STN EN ISO 6892-1, the weld fracture test STN EN ISO 5173 and the Vickers hardness test STN EN ISO 6507-1, the bending impact test STN EN ISO 9016 and the metallographic analysis according to STN EN ISO 17639.

  • Development and investigation of new special steel

    Materials Science. Non-Equilibrium Phase Transformations., Vol. 7 (2021), Issue 3, pg(s) 100-102

    New special high nitrogen steel used in arms industry is developed. The new steel and technology of its production are developed on the basis of the metallurgy under pressure. The mechanical properties by the results of the short -term strength and notchimpact strength tests are determined. The new steel has higher mechanical characteristics in comparison with conventional nitrogen free analogue. Non-destructive control is carried out. Dense structure without defects is established.

  • MATERIALS

    Recent applications of nanoparticles in wood-based panels

    Machines. Technologies. Materials., Vol. 15 (2021), Issue 7, pg(s) 287-290

    Nanocellulose applications in the wood-based panels have gained a great deal in the scientific researches and industrial applications. Utilization of natural and synthetic nanoparticles as reinforcement in the wood-based panels has considerably increased in the last two decades due to their unique properties. The main property of the nanocellulose is its very high surface area. Hereby, the very small use of nanoparticles suh as %1-2 wt% in the composites is enough at a relatively low-cost. Nanoparticles are presently considered to be high-potential reinforcing fillers for the enhancement of the physical, mechanical, electrical/electronic properties, thermal resistivity, fire, durability properties of wood-based panels such as particleboard, fibreboard, oriendted strandboard, and plywood. The nanoparticles are applied to wood based panels dur ing the manufacture and after production. The raw materials such as wood or resin can be treated with nanoparticles or the finished panels can be treated with nanoparticles. In this study, the recent developments in the nano particles, their applications in the wood based panels, and their effects on the panel properties were reviewed

  • Modification of the properties of nanocomposites based on carbon nanostructures

    Materials Science. Non-Equilibrium Phase Transformations., Vol. 7 (2021), Issue 2, pg(s) 46-48

    The electrical and mechanical properties of nanocomposites based on carbon nanostructures has been studied. It is sown that a t a concentration of carbon nanotubes of 15-30 wt. %, the electrical resistance of the samples decreases to 1 order, while its mechanical properties change insignificantly, which is due to the transfer of free electrons from the metal to the CNT, which is comparable to the number of electrical contacts between the constituent elements of the composite and the competition between the numbers of tu nneling and ohmic contacts.

  • TECHNOLOGIES

    Improving the Corrosion Resistance of Carbon Steel Cylindrical Pipe by Nano-Materials Coating, Part -1.

    Machines. Technologies. Materials., Vol. 15 (2021), Issue 3, pg(s) 110-116

    Recent research has shown that the Nano coating materials play a vital role in improving performance of corrosion resistance in hostile environment and enhancing the mechanical properties and reducing the dimension changes. Due to the superior capabilities of Nano coating in many benefits which can be achieved, in addition to corrosion resistance, mechanical properties, make it smoother, stronger and improves its adhesive properties. In this work, the effect of anti-corrosive nanomaterials (Cobalt and Zinc) coating on chemical corrosion behavior and mechanical properties of carbon steel cylindrical pipe were studied in detail. The Nano-coating was done with different thicknesses (300nm,600nm,900nm and 10 μm), then analyzed using ANSYS software technology (version .19).The results showed that there is a strong relationship of corrosion improvement with improving mechanical properties, especially surface deformation resistance, elastic strain and stresses reduction of the inner pipe surface which contains a pressurized corrosive fluid. The maximum improvement was with the thickness of the cobalt coating (10 μm. The result of improvement in corrosion resistance of the cobalt-coated surface is approximately (5.165%) compared to the uncoated surface, also, the results showed an improvement in mechanical resistance and corrosion res istance because of deposition of cobalt particles better than zinc particles in all different thicknesses, with a maximum of about (66%) compared to zinc. Therefore, can conclude that the improving corrosion resistance due to coating with nanomaterials is very promising.

  • MATERIALS

    Improving the Linearized stresses resistance by Nano-Coating, Part-2

    Machines. Technologies. Materials., Vol. 14 (2020), Issue 1, pg(s) 44-54

    The part-2 research is a continuation of part-1 of using a simulation of Nano coating effect on linearized stresses resistance using Finite Element Analysis (FEA) software was carried out. The prime focus here was on exposing a thin Aluminum (Al7075-T6) walled spherical vessel to internal pressure before and after coating, this spherical vessel was coated by Nano- layer using two different materials such as Titanium (Ti) and Nickel (Ni) with thicknesses ranging (100 nm, 500 nm, and 900 nm). Then a comparison of the obtained results was made before and after coating. The results showed that the aluminum Al7075-T6 thin walled spherical vessel successfully coated with Titanium and Nickel separately using ANSYS software. In addition, the results have shown that 100,500 and 900 nm thickness Nickel coated aluminum 7075-T6 thin walled spherical vessel has a better improvement in linearized stresses resistance. These improvements in linearized stresses resistance were equal to 42% with Nickel coating in comparison with Titanium coating of thickness (100, 500 1nd 900 nm). The improvement of the linearized stress highest resistance is about 2.5% and 5% for Ti and Ni, respectively.

  • Improving the mechanical properties of conventional materials by nano-coating, Part-1

    Materials Science. Non-Equilibrium Phase Transformations., Vol. 5 (2019), Issue 4, pg(s) 112-119

    The use of an advanced nanotechnology coating process is absolutely helpful in immensely optimizing the efficiency of mechanical properties of materials such as: Longer service life, ability to tolerate greater loads, ease and low cost of maintenance, the environmental gain in the conservation of resources, improved response in kinetic systems, lower energy consumption, resistance to corrosion, low friction, use of low-cost base material, etc. Metal materials are usually subjected to various surface conditions that might cause stress, strain, deformation, and corrosion. Accordingly, Nano-coating technology is used to enhance the performance of mechanical properties in addition to reduce mechanical failure as much as possible. This research, a simulation of Nano coating effect on some mechanical properties performance using Finite Element Analysis (FEA) software was carried out. The prime focus here was on exposing a thin Aluminum (Al7075-T6) walled spherical vessel to internal pressure before and after coating, this spherical vessel was coated by nano- layer using two different materials such as Titanium (Ti) and Nickel (Ni) with thicknesses ranging (100 nm, 500 nm, and 900 nm). Then a comparison of the obtained results was made before and after coating, the results showed that the aluminum 7075-T6 thin walled spherical vessel was successfully coated with Titanium and Nickel separately using ANSYS software. Also the results showed that 900 nm Nickel coated aluminum 7075-T6 thin walled spherical vessel has a better improvement in mechanical properties. These improvements in mechanical properties were varied between 4.5225% to 20.724% depending on coating thickness and coating material. The Nickel coating has shown higher improvements in comparison with Titanium were observed.

  • Effect of structure and texture on the mechanical characteristics of magnesium alloys processed by equal-channel angular pressing

    Materials Science. Non-Equilibrium Phase Transformations., Vol. 5 (2019), Issue 3, pg(s) 67-70

    ECAP was carried out with a gradual decrease in temperature and an increase in the number of passes on two medical magnesium alloys: WE43 (Mg-3.56%Y-2.20%Nd-0.47%Zr) and ZX10 (Mg-1.0%Zn-0.3%Ca). It was shown that ECAP leads to a significant refinement of the alloys structure. For ZX10 alloy, the average grain size after ECAP decreased from ~ 105 μm in the initial state to 8 ± 0.18 μm in the longitudinal section and to 4 ± 0.19 μm in the transverse one. For the WE43 alloy, the average grain size was changed from 70 μm to 0.69 ± 0.13 μm and the precipitation of particles of the Mg41Nd5 phase with an average size of 0.45 ± 0.18 μm was also discovered. At the same time, the grain refinement led to an increase in the strength characteristics of the both alloys (including fatigue strength), and increased prismatic slip activity (along with the formation of an inclined basal texture in ZX10 alloy) led to an increase in their ductility. The alloy structure formed during the ECAP process does not lead to a decreasing in resistance to chemical corrosion.

  • MATERIALS

    Formation of ZrB2-AlN powder mixture by self-propagating high-temperature synthesis

    Machines. Technologies. Materials., Vol. 13 (2019), Issue 9, pg(s) 414-416

    Formation of ZrB2-AlN mixed powder by self-propagating high-temperature synthesis (SHS) was investigated. Powders of Zr, B, BN and Al (purity >99 %) was used as the starting materials. Two initial mixtures were prepared and mixed at specific ratios. The first mixture was made of Zr and B, which were weighed at stoichiometric amounts to form ZrB2. The second mixture contained Zr, BN and Al; amounts of which were calculated so as to form ZrB2 and AlN.
    The starting powders were mixed in a mortar and pestle, and then the reactant mixture was slightly pressed in a steel die. The SHS reactions were conducted in high purity argon atmosphere, in an SHS chamber. The reactant pellet was ignited from one end with a tungsten wire. The reaction products were examined with scanning electron microscopy and they were subjected to X-ray diffraction analyses.
    It was found that when the reactants contained 40 % mixture-1 and 60 % mixture-2, according to the XRD results of the products, the peaks related to ZrB2 were dominant. The product contained some AlN and ZrN. When the amount of mixture-2 was increased to 90 %, the amounts of AlN and ZrN both were observed to increase. When Al amount in mixture-2 was increased by 30 % and mixture-2 was added as 90% into mixture-1, amount of AlN in the reaction products increased and amount of ZrN decreased. According to SEM examinations, ZrB2 particles were seen to be mixed with AlN particles in the reaction products. Size of ZrB2 particles were about 1 micron and AlN particles were larger.