• 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.

  • MATERIALS

    Effect of aging on Zamak 3

    Machines. Technologies. Materials., Vol. 13 (2019), Issue 8, pg(s) 367-369

    Zamak 3 is a zinc-aluminum alloy with a composition of 3.7-4.3 %Al, <0.05 % Cu, 0.02-0.06 % Mg, rest is Zn. It is well suited for pressure die casting and it results in sufficient mechanical properties and a good surface finish. Zamak 3 is utilized in applications automotive industry, household appliances, in structural applications of buildings, etc. It was reported in literatüre that the mechanical properties of the zamak alloys deteriorate in time at room temperature. In the present study, this effect was investigated by artificial aging of zamak 3 alloy.
    Zamak 3 samples were produced by cutting and melting of Zamak 3 ingots at 500 oC, and casting into steel molds. Aging experiments were conducted by keeping the Zamak 3 samples in a muffle furnace for 24 h at temperatures of 85 oC, 105 oC and 130 oC. Optical and scanning electron microscopy was employed for investigating the microstructure of the samples. Hardness values of the samples were measured by a Brinell hardness tester. A universal testing machine was used for conduction three point bending tests of the samples. It was found that both hardness and bending strength of Zamak 3 alloy decreased with increasing aging temperature. Hardness and strength values of Zamak 3 were 89 HB10 and 490MPa, respectively. After aging at 130 oC hardness and strength values were found to fall to 75 Brinell 10 and 415 MPa, respectively.

  • Evaluation of mechanical properties of ductile cast iron and inverse regression

    Machines. Technologies. Materials., Vol. 13 (2019), Issue 4, pg(s) 183-186

    The evaluation of ductile cast iron is common foundry practice. For the correct non-destructive evaluation (NDE) of mechanical properties (ultimate tensile strength; relative lengthening; Brinell’s hardness; elasticity modulus) by means ultrasonic testing and inverse regression analysis are used.

  • Evaluation of mechanical properties of ductile cast iron and inverse regression

    Materials Science. Non-Equilibrium Phase Transformations., Vol. 5 (2019), Issue 1, pg(s) 28-31

    The evaluation of ductile cast iron is common foundry practice. For the correct non-destructive evaluation (NDE) of mechanical properties (ultimate tensile strength; relative lengthening; Brinell’s hardness; elasticity modulus) by means ultrasonic testing and inverse regression analysis are used.

  • Increase in strength properties of low-carbon steels due to structural transformations at deformation by rotary swaging

    Materials Science. Non-Equilibrium Phase Transformations., Vol. 5 (2019), Issue 1, pg(s) 8-10

    Mechanical properties of low-carbon St.20 and 07G2MFB steels after rotary swaging (RS) were studied. It was established that an increase in strain ratio and decrease in temperature increase strength but decrease plasticity. The ultimate tensile strength of 867-927 MPa was obtained in both steels after deformation at temperature of 400 °C with a true strain ratio of 2.3 at good ductility of 15-17%.

  • Swelling, mechanical and thermal properties of microwave – synthesized intelligent soft materials

    Materials Science. Non-Equilibrium Phase Transformations., Vol. 4 (2018), Issue 3, pg(s) 86-88

    Advances in technology since the second half of the 20th century are followed as well as induced by the development of intelligent materials. These materials are able to respond to external stimuli by measurable changes in structure and intrinsic properties. Stimuli-responsive hydrogels are soft smart materials as they exhibit significant changes in physicochemical properties in response to small external stimuli. Acrylate hydrogels are widely used in applications where their smart and soft nature comes to the fore. Synthesis of those materials by conventional heating is time-consuming and unsuitable from the point of energy and sources saving. Microwave-assisted synthesis is promising method that provides polymerization under the more favourable conditions, reducing the reaction time. The focus of present work was to investigate the swelling behaviour, mechanical and thermal properties of acrylate hydrogels synthesized by microwave heating.

  • NEW METHODS FOR MEASURING THE PROPERTIES OF ANTIBIOGENIC COATINGS OF MEDICAL TITANIUM IMPLANTS FOR TRAUMATOLOGY AND ORTHOPEDICS

    Machines. Technologies. Materials., Vol. 12 (2018), Issue 8, pg(s) 333-337

    The work is a part of researches of the technical characteristics of 20 types of medical titanium implants for traumatology and orthopedics with antibiogenic coating of titanium and hafnium nitrides in accordance with technical conditions of the manufacturer of the implants – JSC “Medmash”, Russia. Based on a titanium alloy the implant with antibiogenic coating is a product coated with titanium and hafnium nitride by high-frequency magnetron sputtering.
    In the present article, the structure, phase composition, distribution of elements on the surface and thickness (Ti-Hf)N-coatings with different hafnium content (Ti:Hf ratio) were investigated. The studies were carried out on model samples in the form of plates of titanium alloy VT6, which were coated with titanium and hafnium nitride by magnetron sputtering. Also, changes in the thickness of the hardness and modulus of elasticity of the coatings were measured by the method of instrumental indentation. The maximum values of hardness (~35 GPa) and modulus of elasticity (~500 GPa) were obtained from coatings of composition (Ti0.85Hf0.15)N and (Ti0.8Hf0.2)N. The coatings with these compositions have the most uniform Hf thickness distribution.

  • INVESTIGATION OF THE EFFECT OF DIAMETERS OF POLYACRYLONITRILE NANO FIBER WITH CARBON NANOTUBE ON MECHANICAL PROPERTIES

    Machines. Technologies. Materials., Vol. 12 (2018), Issue 7, pg(s) 298-301

    In this study, pure polyacrylonitrile (PAN) nano fiber (8 wt. %) and PAN nano fiber with multi-walled carbon nanotubes (MWCNT) were prepared. The content of MWCNT was (1, 3 and 5 wt.%). Electrospin device was used in nanofiber production. Nano diameters of the produced nanofibers were examined by Scanning electron microscopy (SEM). The nanofiber samples were cut 0.5 cm wide and 2 cm long. These samples were subjected to a tensile test on the Shimadzu device. The effect of nanofiber diameters on mechanical properties was investigated. All the MWCNT based composite nanofibers presented larger diameters than those of pure PAN nanofibers. The maximum stress value (76.60 kN) was found to be at PAN nanofiber with 1% MWCNT (average nano fiber diameter is 369.45 nm).

  • TECHNOLOGIES

    QUALITY CONTROL METHODS FOR THE EVALUATION OF QUALITY STABILITY OF REINFORCING BARS

    Machines. Technologies. Materials., Vol. 12 (2018), Issue 6, pg(s) 233-235

    The evaluation of the quality of production process on mechanical properties of reinforcing bars profile 10-32 of steel grade 35GS was performed, obtained in the conditions of the rolling production of JSC “ArcelorMittal Temirtau”. Using a complex quality parameter, the process of rebar production is characterized as stable and controlled.