Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Microhardness


Improvement of Erosion Resistance of Aluminum- Copper Alloy Type 2024 by Plasma Nitriding

Mohammed H. Maseekh; Ali H. Ataiwi; Jamal J. Dawood

Engineering and Technology Journal, 2022, Volume 40, Issue 12, Pages 1-7
DOI: 10.30684/etj.2021.131414.1034

To increase the erosion resistance of 2024 Al alloys, plasma nitriding surface treatment was used. Nitrogen and argon gases are injected into an evacuated chamber until the pressure reaches 15 Pa. The process requirements for normal plasma nitriding were heating at 440˚C for 8 hours, low voltage of 650 V, current of 25 mA, low gas consumption, and no air pollution. A continuous nitriding layer of AlN was formed. The microhardness reached a maximum value of 170 HV, about 3 times higher than that Al melts at, is transported upward through voids and capillaries in the AlN structures, and reacted with N plasma in the melt surface. The growth of the AlN structures promotes this transport of un-nitride alloy subjected to the same heat treatments. As a result, the erosion rate of the nitrided samples decreased by 10% when compared to the ones that are not nitrided.

Effect of CO2 Laser Fluence in Cladding Process on the Microstructure of Cold Rolled 0.2 % Carbon Steel

Suhair A. Hussein; Mohammed Kadhim; Mahdi M. Hanon

Engineering and Technology Journal, 2021, Volume 39, Issue 7, Pages 1052-1059
DOI: 10.30684/etj.v39i7.1475

In this article a 1.8kW continuous wave of high power CO2 laser was used to clad of a titular composition of Ni – 10 wt% Al powder on cold rolled 0.2% carbon steel substrate. The feed rate was kept constant after many preliminary claddings at approximately 11 g/min.  In order to produce clads with different specific energies and interaction times, different traverse speeds were used in the range of 1.5 to 12.5 mm/s. The microstructure of substrate was changed at the heat affected zones under the variety of specific energies. The cladded coatings showed the presence of ɣ solid solution and β (NiAlFe) phases. A strong metallurgical bonding produced between the substrate and the clad coat at fluence higher than 48 J/mm2. The changing in microstructure were observed using both microscope and SEM. The microhardness was evaluated using Vickerʼs microhardness test. The microstructure of the substrate was ferrite and pearlite transformed to martensite at the region adjacent to the clad interface. It followed by a three regions can be classified, a grain growth zone (large grains of austenite/ferrite and pearlite), recrystallization zone (fine grains of austenite/ferrite and pearlite) and recovery zone (the structure has a little changes from the structure of low carbon steel). The microhardness testing result showed higher values for the clad regions compared with substrate. This study emphasize the possibility to develop a temporary new graded material.

Characterization of Nb2O5-Ni Coating Prepared by DC Sputtering

Hiyam M. Jedy; Rana A. Anaee; Abdullah A. Abdulkarim

Engineering and Technology Journal, 2021, Volume 39, Issue 4A, Pages 565-572
DOI: 10.30684/etj.v39i4A.1902

The Nb2O5-Ni coating was processed using DC sputtering on structural steel and study characterization of composite coating SEM/EDS inspection indicated clearly perfect incorporation of Nb2O5 within the nickel rich. Increasing in surface roughness and decreasing in average diameters of particles were obtained for coated surface compared with uncoated surface from AFM analysis, in addition, microhardness test and thickness test showed that increasing of the hardness value to 163 HV for Nb2O5 - Ni composite coating compared to 132 HV for uncoated samples, the hardness for Ni coating also increasing to155 HV and the thickness for Nb2O5-Ni composite coatings increased significantly compared to uncoated samples.

Influence of SAW Welding Parameters on Microhardness of Steel A516-Gr60

Sadeq H. Bakhy; Samir A. Amin; Fouad A. Abdullah

Engineering and Technology Journal, 2018, Volume 36, Issue 10A, Pages 1039-1047
DOI: 10.30684/etj.36.10A.4

Submerged Arc Welding (SAW) process is generally used for industries, such as petroleum storage tanks, pressure vessels, and structural components.
Good mechanical properties of welded joint lead to crack-free strong joints. In this research, included angle, current, welding travel speed and arc voltage were utilized as welding parameters to weld ASTM A516 Grade 60 (low carbon steel). The experiments were carried out according to a design matrix that established by DOE (Version10) with RSM technique. Microhardness of welded samples was measured by a Digital Microhardness Tester, and then RSM technique was used to model and optimize the microhardness based on the welding parameters. The results showed that the including angle and welding current have a great effect on the microhardness. The optimum solution for minimum microhardness was found at 450 Amp welding current, 38 cpm welding speed, 34-volt arc voltage and included angle of 60⁰. The optimum value of microhardness was (186.7 HV). Eventually, the experimental and predicted results of microhardness were found in good agreement with 4.6%. maximum error.

Effect of Friction Stir Processing (FSP) to the Some Properties of Pure Copper Welded by Friction Stir Welding

Mais A. Abdulkareem

Engineering and Technology Journal, 2018, Volume 36, Issue 9A, Pages 985-990
DOI: 10.30684/etj.36.9A.7

Friction stir processing (FSP) is an innovative technique of varying the metallic features by intense, local plastic deforming. Accordingly, materials are stirred with no altering the phase via melting or otherwise to produce a microstructure with equiaxed and fine grains. This method enhances the microstructural features of metals. In This study the microstructure and the mechanical features including (tensile strength and microhardness), and radiographic inspection results are studied. All specimens of pure copper use in the (FSW) and (FSP) have variable rotating speed (900, 1200, and 1600 rpm) with constant feed speed (40 mm/min). The most remarkable results, the ultimate tensile strength for FSW and FSP at (1200 RPM and 40 mm/min) with the values of 250.4 MPa for FSW and 261..2 MPa for FSP and the efficiency reached 92.7% and 96.3% for FSP and FSW, respectively. The high hardness in the same sample was 118 HV for FSW and 135 HV for FSP. The microstructure at welding zones, specially nugget zone, is improved by the friction stir processing. Radiographic examination showed incomplete fusion of welding joint without defect.

Surface Modification of Red Brass Alloy by Using Laser Technique

Abdulhadi Kadhim; Inmar N.Ghazi; Amjed Razzaq.Hussein

Engineering and Technology Journal, 2016, Volume 34, Issue 7, Pages 1439-1444
DOI: 10.30684/etj.34.7A.15

Laser shock processing technique was performed on red brass alloy type C83300 specimens for the purpose ofstudy its effect on the mechanical properties such as micro-hardness and surface roughness. LSP experimental setup system involved Q-switched Nd:YaG laser of wavelength of 1064nm and 10 ns laser pulse . Double distilled deionized water (DDDW) is used as the transparent confining layer. The effects of the LSP parameters as laser pulse energy, number of laser pulses and thickness of confinement layer on the surface micro-hardness, and surface roughness were investigated. The experimental results show that, the surface roughness and micro-hardness values increased when the laser parameters (mentioned above) have been increased and the maximum value of micro-hardness generated near the surface due to LSP. The optimum thickness of DDDW layer was 4mm. After this thickness (4mm) ,the results of microhardness and surface roughness are reduced due to the absorption of laser pulse energy by the confinement layer .

Evaluate the Performance of the System Thermal Evaporatingin Vacuum for Metal Type Varian USA

Alaa A. Abdul- Hameed; Saria D. M.Al-Algawi

Engineering and Technology Journal, 2015, Volume 33, Issue 3, Pages 76-82

Evaporation method was used in order to prepare films of pure gold on substrate of n –Si (111) and studied the influence at different parameters deposition, such as the weight of the material used (gold) , the weight of coating deposited , the effect of each of the temperature annealing , deposition rate , thickness coatings deposited, as well as the study of open porosity.
The results showed an increase in the thickness of coating with the increasing of the weight of the material used and these are different deposition ,sedimentation rates. A decrease in the open porosity with increase temperature annealing. A decrease in the density of the coating deposited with the increase in thickness due to a decrease in the stacking layers deposited.
It was concluded that the efficiency of the deposited equal to 94 % for the system, and that the system can deposition coatings thickness of gold ranges from (0-7.5μm).

The Influence of Magnesia Addition and Sintering Temperature on The Properties of Synthesized Electrical Porcelain

Fadhil A. Chyad; Fadhaa G. Salem; Innam W. Waten; Zahraa F.Attiya

Engineering and Technology Journal, 2015, Volume 33, Issue 2 engineering, Pages 285-293
DOI: 10.30684/etj.33.2A.1

The influence ofmagnesia (MgO) content at different sintering temperatures on the physical and dielectric properties of synthesized electrical porcelain was investigatied.Feldspar is one of the major components of porcelain,since feldspar is not available in Iraq, so it was synthesized from Iraqi raw materials.MgO was progressively added in the range (2-30 wt. %) into electrical porcelain. The composed bodies were sintered at temperature in the range(1200-1350 C),Physical properties such bulk density, open porosity beside the Vickers microhardness and dielectric properties such as dielectric constant, loss tangent and dielectric loss factor were measured. The improvement of these properties could associate with an increasing of MgOadditive and sintering temperatures. Bulk density, microhardness and dielectric constant are increased with the increasing of MgO content and sintering temperatures. The results reveal that the highest value of density at 30wt. %MgO and at 1350 C for density, hardness and dielectric constant, while it has the lowest value for porosity and loss tangent.

Synthesis of B4C/YTZP Composite Powder and Studying Effect of its Addition on Mechanical Properties of B4C

Fadhil A. Chyad; Mohammed H. AL-Taie; Hussein AlaaJaber

Engineering and Technology Journal, 2014, Volume 32, Issue 5, Pages 1158-1170

In this research B4C powder have been coated with yttria stabilized tetragonal zirconia polycrystalline (YTZP) (ZrO2 – 6wt% Y2O3) by using sol-gel method in order to obtain on composite powder (B4C core/ YTZP shell, 1/1 wt%). Zirconium oxychloride (ZrOCl2.8H2O) and yttrium nitrate (Y(NO3)3.6H2O) were used as the precursors for synthesis of the YTZP compound. The coated B4C powder was then used as additive powder to B4C. It was mixed with different percentages for making ceramic–ceramic composite samples. The YTZP weight percentages added to the B4C were in the range (0–12.5) wt%. The samples sintered by using spark plasma sintering technique at 1800 and 1900°C for 5 min. Density and mechanical properties (Vickers microhardness, fracturetoughness and fracturestrength) for the sintered samples were measured. The results show that the best YTZP additions to the B4C that have good mechanical properties were ranged 5 – 7.5 wt%.

Synthesis and Studying SomeMechanical Properties of Nanocomposite

Fadhil A. Chyad; Abdul-Raheem K.Abid Ali; Auday A. Mehatlaf

Engineering and Technology Journal, 2013, Volume 31, Issue 7, Pages 1221-1228

This study aims to synthesis a nanocomposite from Al2O3 – Cr2O3 and studying some of its mechanical properties like microhardness and fracture strength.
X-Ray diffraction patterns shows a good crystallinity of the composite with very sharp and neat peaks. TEM photographs shows the good distribution of the particles which have an average particle size of (3-6 nm). The microhardness is increased with the increasing of sintering temperatures having the height value at 15% chromia while the fracture strength behaves as a bell shape having again the height value at 15% chromia.

Effect of Laser Surface Treatment on Mechanical Properties of CK45 Steel

Sabah N. mahmood; Khansaa Dawood Selman

Engineering and Technology Journal, 2011, Volume 29, Issue 8, Pages 1610-1618

The research aims to study the effect of laser surface treatment on mechanical properties of CK45 steel which is widely used in Bolts, Axles Various,Connecting Rods and Hydraulic clamps. Trails of laser hardening were carried out by using CW Nd: YAG laser with different powers 2.7, 3.3, and 4.3 Watt. Mechanical tests were done for the specimens who were used in the research before and after treated by laser such as: Tensile test, Micro hardness. Also grain size measurement and microstructural evaluation were done by using
computerized optical microscope. The results show that improvement in
mechanical properties at laser power 4.3 watt obviously when compared with other laser powers. From tensile test we show that increasing in yield strength, ultimate tensile strength Poisson's ratio and plasticity constant (k). Also decreasing in Young modulus, Rigidity of modulus and strain hardening coefficient (n). While microhardness results show that the highest value was obtained at laser with 4.3
watt power and decreased far from the surface. Metallographic of the specimen show that refining in grains size after the treatment with laser.

One Parameter Composite Semigroups of Linear Bounded Operators in Strong Operator Topology of Schatten Class Cp

Samir Kasim Hassan; Al-Taie M; Al-Malki Anam; Al-Attar Abeer; Mustafa Khaleel Ismael; Fatema Ahmed Sadeq; Radhi A .Zboon; Jehad R.Kider; Samir K .Hassan; Hussain J. M. Alalkawi; Raad H. Majid; Rawaa A. Alomairy; Luma Abdul Ghani Zghair; Hadia Kadhim J.Al-Ogili; Assifa M. Mohamad; Abbas Sheyaa Alwan; Haider L. Aneed; Assim H Yousif; Salema Sultan Salman; Abbas Hussien Miry; Abduladhem A.Ali; Mohammed Zeki Al-Faiz; Sabah N. mahmood; Khansaa Dawood Selman; Shaymaa Tareq Kadhim

Engineering and Technology Journal, 2011, Volume 29, Issue 8, Pages 1463-1470

For semigroups of linear bounded operators on Hilbert spaces, the problem of
being in Cp , 0 Keywords

Study The Effect of Co Concentration In Nico Thin Films on Some Structure And Mechanical Properties

Alaa A. Abdul-Hamead

Engineering and Technology Journal, 2010, Volume 28, Issue 12, Pages 2486-2496

Electroplating process has been used to prepare Magnetic NiCo alloys thin
film with thickness of 1μm on brass alloy substrate using different Co
concentrations .Surface morphology, XRD, atomic absorption, apparent density,
open porosity, stresses and microhardness of pure and alloys thin film has been
investigated. Results indicated that the pure and alloy of thin films was
polycrstaline with (111) domain orientation changed to (101) with increment Co
deposited percentage, which is spontaneously increase with Co molarity increased
in the deposition solution.Microstructure for thin films change from nodular
structure to pyramidal and dendritic structure with changing Co content in film.
Apparent density for prepared thin films was less than theoretical density about
(8g/cm3), and varying with actual Co deposited content. Open porosity also
reduced in general with increment of Co content. Mechanical properties shows
alteration in internal stress behavior of deposited thin films from compressive
stress to tensile stress at (0.05M) of Co. Microhadness also increased with
increasing in the Co percentage in deposited thin films,to about(467Kg/mm2).

Effect of Laser Surface Treatment on Wear Resistance of 100Cr6 Steel

Khansaa Dawood Salman

Engineering and Technology Journal, 2009, Volume 27, Issue 6, Pages 1151-1161

The effect of laser surface heat treatment on wear resistance of 100Cr6 steel was
investigated. In this work, 100Cr6 steel which is widely used in many industrial of automobiles
hardened by using Nd: glass laser (l=1.060mm, t=300ms). Three different laser energies have been
used to perform hardening (0.3, 0.58 and 0.93 Joule). A pin-on-disc technique has been used to
evaluate wear rate of the specimens as-received and specimens treated by Nd: glass laser at
different applied loads and different sliding speeds with 420 r.p.m and 45 HRC of rotating
disc. The results show that the wear rate increases with increasing applied load and decreases with
increasing sliding speed, wear rate for laser energy 0.93 J less than another energies 0.3 and 0.5 J.
Also the microhardness decreases with increasing in depth of hardening, and the microhardness
for laser energy 0.93 J more than another energies for the same depth.