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Number of results: 3537
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Abstract

In this case ceramic layers from Metco ZrO2 and Al2O3 powders mixture (25/75; 50/50 and 75/25) were obtained through atmospheric plasma spraying (APS) after five passes on low carbon steel substrate. The sample surfaces mechanically grinded (160-2400) before and after ceramic layer deposition. Powder’s mixtures and the surface of ceramic thin layers were analyzed through: scanning electron microscopy (SEM). In order to understand the effect of surface wettability of the ceramic layers, before and after grinding the surface, three different liquids were used. Experimental results confirm the modification of the steel substrate surface characteristic from hydrophilic to hydrophobic when the ceramic layer was deposited. Surface free energy of hydration increases for all the samples with zirconia percentage addition before polishing process.
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Authors and Affiliations

M. Luțcanu
1 2
ORCID: ORCID
M. Coteață
3
ORCID: ORCID
M.A. Bernevig
1
ORCID: ORCID
C.D. Nechifor
2
ORCID: ORCID
M.M. Cazacu
2
ORCID: ORCID
P. Paraschiv
4
ORCID: ORCID
B. Istrate
5
ORCID: ORCID
G. Bădărău
1
ORCID: ORCID
I.G. Sandu
1
ORCID: ORCID
N. Cimpoeșu
1
ORCID: ORCID

  1. Gheorghe Asachi Technical University of Iasi, Faculty of Materials Science and Engineering, Prof.dr.doc. D. Mangeron no. 41 Street, 700050 Iasi, Romania
  2. "Gheorghe Asachi” Technical University of Iasi, Department of Physics, 700050 Iasi, Romania
  3. Gheorghe Asachi Tech Univ Iasi, Dept Machine Mfg Technol, 59A D Mangeron Blvd, Iasi 700050, Romania
  4. “Gheorghe Asachi” Technical University of Iasi, Department of Sport, 700050 Iasi, Romania
  5. Gheorghe Asachi Tech Univ Iasi, Fac Mech Engn 43 D Mangeron St, Iasi 700050, Romania
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Abstract

AlCrFeCuCoNi high entropy particles were alloyed on Ti-6Al-4V surface using Plasma transferred arc (PTA) process. PTA alloyed surfaces were investigated for their phase formation, microhardness improvement and wear behaviour. The various wear mechanism and their corresponding surface roughness were studied. The results revealed that the dual phase of BCC and FCC microstructure along with some intermetallic compounds were grown in the alloyed region through the PTA technique and good metallurgical bonding of the alloyed region with the base material were achieved. The PTA alloyed region exhibited a hardness of 718 HV0.2 which is 2.2 times higher than the hardness of base material. The PTA alloyed samples showed higher wear resistance due to the solid solution strengthening as the HEA has high entropy of mixing that leads to the reduction of free energy of the alloyed region. It exhibited better interconnection of the coated material and superior metallurgical bonding to the base material. Frictional heat produced during the wear test has promoted the formation of FeO, Cr2O3, CuO, NiO and Al2O3 oxide film on the PTA alloyed sample. These oxide films act as a barrier between two mating surfaces and improve the tribo performance of the PTA alloyed sample.
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Authors and Affiliations

G. Prabu
1
Muthukannan Duraiselvam
1

  1. National Institute of Technology, Department of Production Engineering, Tiruchirappalli, India
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Abstract

In the past decades, Mg alloys have been studied intensively as potential orthopedic applications. The present research work, the FEA of the obtained contact stresses in the case of the load applied on Mg-0.5Ca-xMn alloys has been investigated. It has been used the NCB Curved Femur Shaft Plate type as a model in order to establish the necessary modeling parameters. The objective of the present work was to highlight the strain values at the contact point on the surface of the Mg-0.5Ca-xMn alloys. The results showed that the highest stresses observed near the gaps of the plate and in the screws. It means that all mechanical loads are sustained by the plate and screws, and the patient’s femur can be recovered.
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Authors and Affiliations

R.O. Nastasa
1
ORCID: ORCID
A. Tufescu
1
ORCID: ORCID
C. Munteanu
1 2
ORCID: ORCID
B. Istrate
1
ORCID: ORCID
A. Przybył
3
ORCID: ORCID
G. Ianus
1
ORCID: ORCID

  1. Gheorghe Asachi Technical University, Faculty of Mechanical Engineering, Blvd. Mangeron, No. 43, 700050, Iasi, Romania
  2. Technical Science Academy of Romania, 26 Dacia Blvd, Bucharest 030167, Romania
  3. Częstochowa University of Technology, Department of Physics, 19 Armii Krajowej Av., 42-200 Częstochowa, Poland
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Abstract

Plates of AZ91 magnesium alloy were butt-welded using a CO2 laser. The non-equilibrium solidification of the laser-melted metal caused fragmentation of the weld microstructure as well as the supersaturation of a solid solution of aluminium in magnesium, which enabled the T5 ageing of the weld. The weld proved to be a mechanically stable part of the joint; all the tensile-tested specimens, both as-welded and post-weld T5 aged, fractured outside it. During the ageing of the supersaturated joint, which involved heat treating it to the T6 condition, the weld was the region where discontinuous precipitation was observed and this was the location of fracture in the tensile specimens. Thus, the strength properties of welded, supersaturated and aged AZ91 were much worse than when the non-welded material was T6 tempered.
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Authors and Affiliations

A. Dziadoń
1
ORCID: ORCID
E. Musiał
1

  1. Kielce University of Technology, Metals Science and Materials Technologies, 7 Tysiąclecia Państwa Polskiego Av., 25-314, Kielce, Poland
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Abstract

Effect of annealing treatment on deep drawing behavior of hot-rolled Q235 carbon steel/410/304 stainless steel three-layer composite plate was investigated. Deep drawability of the unannealed composite plates exhibits a sharp difference for various contact surfaces with the die. The limit drawing ratio (LDR) of the composite plate with the carbon steel contacting the die is 1.75, while it is 1.83 with the stainless steel contacting the die due to the different mechanical responses to the tensile stress at the corner of the die. After annealing at 900°C for 2 h, however, the deep drawabilities of the composite plates both for various contact surfaces with the die are significantly improved and becomes almost identical, which are attributed to the stress relief, the enhanced ductility and the improved interface bonding strength of the hot-rolled component plates during annealing.
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Authors and Affiliations

Zehua Lv
1 2 3
Zhixiong Zhang
1 2 3
Jianchao Han
1 2 3
Tao Wang
1 2 3
ORCID: ORCID

  1. Taiyuan University of Technology, College of Mechanical and Vehicle Engineering, Taiyuan 030024, PR China
  2. Taiyuan University of Technology, Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment, Ministry of Education, Taiyuan 030024, PR China
  3. Taiyuan University of Technology, Tyut-Uow Joint Research Centre, Taiyuan 030024, PR China
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Abstract

The effects of hydrogen absorption and manganese substitution on structural, electronic, optical, and thermoelectric properties of silicon-carbon nanotubes (SiCNT) are studied using the density functional theory and the GGA approximation. An examination of the PDOS curves and the electronic band structure showed that the Mn substitution leads to an increase in magnetic anisotropy and the occurrence of semi-metallic behavior and that the hydrogen absorption shifts the band gap toward the lower energies. A study of these nanostructures’ thermoelectric behavior reveals that the H absorption leads to a significant escalation in the figure of merit of the SiCNT to about 1.6 in the room temperature range. The effects of the H absorption on this nanotube’s optical properties, including the dielectric functions and its absorption spectra, are also investigated.
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Authors and Affiliations

Amir Toofani Shahraki
1
Heydar Ali Shafiei Gol
1
Salimeh Kimiagar
2
Naser Zare Dehnavi
1

  1. Department of Physics, Central Tehran Branch, Islamic Azad University, Tehran, Iran
  2. Nano Research Lab (NRL), Department of Physics, Central Tehran Branch, Islamic Azad University, Tehran, Iran
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Abstract

Quality of 3d model in simple way translates into quality of final product, obtained from 3d printing. 3d CAx software give possibility to create enormous number of shapes – doesn’t matter solids or surfaces. The question is where is the frontier between quality of 3d model and a value for money of the completed print? Is it always necessary to create as good model as possible? This paper will focus on preparation of 3d models, based on primitives and will show connection between quality of mesh, its size and deviations and quality of obtained samples, in same manufacturing conditions.
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Authors and Affiliations

M. Tagowski
1
ORCID: ORCID

  1. Częstochowa University of Technology, Faculty of Technology and Automation, 21. Armii Krajowej Av., 42-201 Częstochowa, Poland
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Abstract

The versatile application of titanium alloy in the aerospace industry and it’s hard to machine characteristics focus towards the additive manufacturing. The Ti-6Al-4V alloy is manufactured using the electron beam source with a novel method of prepositioned titanium alloy wires. The tribology of the additive manufactured titanium alloy under dry sliding condition is experimented and analysed using Taguchi technique. The targeted objective of minimum tribological responses are attained with the identified optimal parameters as load – 9.81 N, sliding velocity – 3 m/s, sliding distance – 3000 m for minimum specific wear rate and load – 9.81 N, sliding velocity – 3 m/s, sliding distance – 1000 m for minimum coefficient of friction. Among the parameters tested, load is found to be the dominant factor on the tribology of additively manufactured titanium alloy. The morphological analysis on the worn surface and debris revealed the existence of abrasion, delamination and adhesion wear mechanisms. The increase in the load dominantly showed the appearance of delamination mechanism.
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Authors and Affiliations

A. Manjunath
1
ORCID: ORCID
V. Anandakrishnan
2
ORCID: ORCID
S. Ramachandra
1
ORCID: ORCID
K. Parthiban
1
ORCID: ORCID
S. Sathish
3
ORCID: ORCID

  1. Gas Turbine Research Establishment, Defence Research & Development Organization, Bangalore, Karnataka-560093, India
  2. Department of Production Engineering, National Institute of Technology Tiruchirapalli, Tiruchirappalli – 620015, Tamil Nadu, India
  3. Department of Mechatronics Engineering, K.S. Rangasamy College of Technology, Tiruchengode, Namakkal – 637215, Tamil Nadu, India
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Abstract

The one-part geopolymer binder was synthesis from the mixing of aluminosilicate material with solid alkali activators. The properties of one-part geopolymers vary according to the type and amount of solid alkali activators used. This paper presents the effect of various sodium metasilicate-to-sodium aluminate (NaAlO2/Na2SiO3) ratios on fly ash-based one-part geopolymer. The NaAlO2/Na2SiO3 ratios were set at 1.0 to 3.0. Setting time of fresh one-part geopolymer was examined through Vicat needle apparatus. Mechanical and microstructural properties of developed specimens were analysed after 28 days of curing in ambient condition. The study concluded that an increase in NaAlO2 content delayed the setting time of one-part geopolymer paste. The highest compressive strength was achieved at the NaAlO2/Na2SiO3 ratio of 2.5, which was 33.65 MPa. The microstructural analysis revealed a homogeneous structure at the optimum ratio. While the sodium aluminium silicate hydrate (N-A-S-H) and anorthite phases were detected from the XRD analysis.
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Authors and Affiliations

Ooi Wan-En
1 2
Yun-Ming Liew
1 2
ORCID: ORCID
Heah Cheng Yong
2 3
ORCID: ORCID
Ho Li-Ngee
2 4
Mohd Mustafa Al Bakri Abdullah
1 2
ORCID: ORCID
Ong Shee-Ween
1 2
Andrei Victor Sandu
5
ORCID: ORCID

  1. Universiti Malaysia Perlis (UNIMAP), Center of Excellence Geopolymer and Green Technology (CEGEOGTECH), Kangar, 01000 Perlis, Malaysia
  2. Universiti Malaysia Perlis (UNIMAP), Faculty of Chemical Engineering Technology, Kangar, 01000 Perlis, Malaysia
  3. Universiti Malaysia Perlis (UNIMAP), Faculty of Mechanical Engineering Technology, Kangar, 01000 Perlis, Malaysia
  4. Universiti Malaysia Perlis (UNIMAP), Centre of Excellence Frontier Materials Research, FRONTMATEKANGAR, 01000 Perlis, Malaysia
  5. Gheorghe Asachi Technical University of Iasi, Faculty of Materials Science and Engineering, 700050, Iasi, Romania
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Abstract

The following article presents the results of selected properties of regranulates of polyamide 6.6, regranules of polyamide contaminated with polypropylene and regranules of polyamide contaminated with silicone. The tested materials came from the reprocessing of polyamides 6.6 originally derived from production of airbags from renowned world producers (material for the research came from production waste). The results of examination were referred to regranulates of uncontaminated polyamide but also obtained from waste from the production of these airbags.
The influence of impurities on properties of regranulates such as their density and melt flow index was assessed. The tests allowed to show a significant impact of impurities on the density but above all on the mass and volume flow rate index which ranged from 47 to 116 g/10 min.
In the case of standardized test specimens selected thermal and mechanical properties were analyzed. Differential scanning calorimetry was used to assess the impact of impurities on the thermal properties of polyamides, allowing primarily identification of materials and impurities (especially polypropylene) as well as characteristic temperatures and the enthalpy of melting of the materials being analyzed. The mechanical properties were assessed using a DMA device. DMA research allowed to determine changes in mechanical properties in a wide temperature range of tested materials. It allowed to obtain full characteristics of changes in material stiffness under the influence of two factors, i.e. temperature and content of impurities, like polypropylene or silicone.
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Authors and Affiliations

T. Stachowiak
1
ORCID: ORCID

  1. Częstochowa University of Technology, Faculty of Mechanical Engineering and Computer Science, Department of Technology and Automation, Częstochowa 42-200, 69 J.H. Dąbrowskiego Str., Poland

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