research centers


Search results: Found 16

Listing 1 - 10 of 16 << page
of 2
>>
Sort by

Article
Effect of Zn % and Thermomechanical Treatments on the Mechanical Properties of Al-Zn-Mg Alloys
تأثير نسب الخارصين والمعاملات الثرموديناميكية على الخواص الميكانيكية لسبائك ألمنيوم_خار صين_مغنسيوم

Author: Ali H. Ataiwi
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2007 Volume: 25 Issue: 7 Pages: 849-862
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

The aging kinetics and the coupling between plastic deformation andsubsequent aging on a set of Al-Zn-Mg alloys having different Zn-content(6.33%, 7%, 7.5% and 8%) are investigated. These alloys are produced withan extreme care during melting, alloying and sampling where the bestconditions of alloying are adopted .The response to multi thermomechanicaltreatments practices are reported, where the combination between rollingpractice and aging is monitored by hardness measurements, tensile, impacttoughness measurements in addition to x-ray diffraction testing. The studyproves that, the zinc percent has a very important role in the precipitationhardening sequence of tested alloy; this effect is concentrated on the speedingup the kinetics of hardening by increasing the density and stability of GPzones and μ'-phase.

تم دراسة آليات التعتيق والموالفة بين التشكيل اللدن والتعتيق اللاحق على مجموعة منالسبائك الثلاثية ذات السلس لة 7000 (ألمنيوم – خار صين – مغنيسيوم ) ذات قيم متغيره من8% ). حيث تم إنتاج هذه السبائك خلال الصهر والتشبيك , %7.5 , %7 , % الخارصين 6.33وتصنيع العينات بدقة عالية وتم اختيار أفضلها ، حيث تم تسجيل استجابة هذه السبائكللمعاملات الثرموميكانيك ية من حيث إجراء الدرفلة و التعتيق و من ثم قياس الصلادةومقاومة الشد والصدمة إضافة لفحوصات حيود الأشعة السينية . وقد أثبتت الدراسة أن لنسبةالخارصين دور كبير على عملية التصليد بالترسيب حيث تركز هذا التأثير على تسريع آلية.μ´ التصليد من خلال زيادة كثافة واستقرار مجالات كنيه–بريستون والطور

Keywords


Article
Study Some of the Structure Properties of ZrO2 Ceramic Coats Prepared by Spray Pyrolysis Method
دراسة بعض الخواص التركيبية لطلاءات الزركونيا ZrO2 السيراميكية المحضرة بطريقة الرش الكيمياوي الحراري

Authors: .Ali H. Ataiwi --- Alaa A. Abdul-Hamead
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2009 Volume: 27 Issue: 16 Pages: 2918-2930
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

In the present work pure and doped ZrO2 with (Al and Co 5wt%) thin film has been deposited on glass and stainless steel 304 substrates by spray pyrolysis technique The film were tested by XRD and the topography of the films has been examined by using SEM. Open porosity, rate of deposition, surface roughness and apparent density was calculated . The results of XRD show that the films was crystalline with tetragonalphase of ZrO2 .The grain size of pure ZrO2 was (148.6 nm) and lattice strains was 0.27%.Apparent density for pure ZrO2 and with(Al,Co) dopents were (4.5,5 and 5.5 g/cm3) respectively ,and open porosity for the films are respectively(2.5,2 and 1.5 pore/cm2). Surface roughness (Ra) was(0.218μ m) for pure ZrO2 film and(0.904μm) for ZrO2 doped with Al.

النقية و الزركونيا المشابة بنوعين من ZrO في هذا البحث تم ترسيب طلاء من الزركونيا 2 5)لكل wt%) المعادن وهي الالمنيوم و الكوبلت بطريقة الرش الكيميائي الحراري وبنسب وزنيه بلغت منهما على قواعد من الزجاج والفولاذ 304 .تم اولا تحليل الاغشية بأستخدام حيود الأشعة السينية و فحص البنية المجهرية باستخدام المجهر ا لالكتروني الماسح وكذلك تم قياس المسامية XRDان XRD المفتوحة و حساب الكثافة الظاهرية و معدل الترسيب,و الخشونة أيضا . بينت نتائج الاغشية المترسبة كانت متبلورة والطور المتكون هو(مربع الزوايا و الإضلاع) و الحجم الحبيبي 148.6 ) ونسبة الاجهادات الداخلية( % 0.27 ).بلغت قيمة الكثافة الظاهرية nm ) للزركونيا النقية بلغ (5 ,5.5g/cm 4.5 )و للأغشية المشابه بالالمنيوم و الكوبلت هي ( 3 g/cm لاغشية الزركونيا النقية ( 3 2.5 ) و للمشابة بالالمنيوم و الكوبلت Pore/cm على الترتيب, قيمة المسامية للزركونيا النقية بلغت ( 2 (Ra=0.218μ 1.5,2 ) على التوالي .بلغت قيمة الخشونة السطحية لاغشية الزركونيا النقية Pore/cm2) .(0.904μm) و المشابة بالألمنيوم m)

Keywords


Article
Autopolymerizing acrylic resin is one of the most frequently used materials in dentistry, but it has relatively poor mechanical properties This study investigated the effect of the addition of poly vinyl pyrrolidone on transverse strength, impact strength and surface roughness of autopolymerzing acrylic resin. A total of 60 specimens were prepared, 30 specimens of each conventional and modified autoplymerizing acrylic.20 specimens of each groups were fabricated with dimensions of (64×10×2.5) mm to conduct the transverse strength and surface roughness tests, while the remaining 10 specimens of each group were fabricated with dimensions of (80×10×4) mm to perform the impact strength test. The results of this study showed that the modified autopolytmerized acrylic had significantly higher transverse strength, and significantly lower surface roughness values while there was no significant differences in impact strength value. It can be concluded that addition of Polyvinylpyrrolidone can improve transverse strength and surface roughness of autopolymerizing acrylic resin.

Author: Ali H. Ataiwi علي حسين عتيوي
Journal: Tikrit Journal for Dental Sciences مجلة تكريت لعلوم طب الاسنان ISSN: 20731213 Year: 2013 Volume: 2 Issue: 2 Pages: 145-153
Publisher: Tikrit University جامعة تكريت

Loading...
Loading...
Abstract

This work involves study the effect of tobacco smoking (cigarette, water-pipe smoking) yields on the corrosion of dental alloys (Co-Cr-Mo, Ni-Cr and Ti-Al-V alloy) in artificial saliva with pH=4 and temperature of 37oC. This study was performed with electrochemical technique by using potentiostat to predict the potentiodynamic polarization and cyclic polarization. Some corrosion parameters were measured for comparison among the dental alloys. Generally, the presence of tobacco smoking yields shift the corrosion rate (CR) to higher values, and the data of corrosion rate indicate that the risk of waterpipe smoking more than cigarette smoking for three dental alloys. Increasing of anodic Tafel slopes inferred that the rate of change of current with change of potential was smaller during cathodic polarization than during anodic polarization.


Article
DESTABILIZATION HEAT TREATMENT EFFECT ON EROSIVE WEAR CHARACTERISTICS OF HIGH CHROMIUM WHITE CAST IRON

Authors: Ali H. Ataiwi --- Israa F. Yousif
Journal: KUFA JOURNAL OF ENGINEERING مجلة الكوفة الهندسية ISSN: 25230018 Year: 2018 Volume: 9 Issue: 2 Pages: 45-56
Publisher: University of Kufa جامعة الكوفة

Loading...
Loading...
Abstract

In the present investigation, erosive wear property of high chromium white cast irons (HCWI) is reported. HCWI were destabilized at two different temperatures of 955oC and 1100°C, air cooling followed by tempering heat treatment at 400°C and 700°C at each destabilized temperature. Erosion damage was evaluated by the removed material mass at impact angle 45° and time of 10 Hours. The surface metal flow was observed. Surface morphology of each specimen was characterized with scanning electron microscopy (SEM). The effect of heat treatment on differences in wear features of specimens is discussed. Experiment showed that the erosion rate of specimen destabilized at 1100°C, air cooled followed by tempering at 400°C air cooling is the best than other treatments. The hardness of test surface by this treatment increased from the initial 57 to 58 HRC after 10 hour. It showed that austenite in the surface structure has been transformed to martensite , which hardened the surface. Similarly, work- hardening effect also occurred on specimen destabilized at 955°C, air cooled followed by tempering at 400oC, air cooling to make its surface hardness increased to 59 HRC. It was shown that HCWI series heat treated at 955°C and 1100°C and tempered at 400°C have a very good erosive wear resistance and they are expected to find wide application as wear-resistant materials.


Article
CONSTRUCTION OF SLURRY JET EROSION TESTER AND THE EFFECT OF PARTICLE SIZE ON SLURRY EROSION

Authors: Israa F. Yousif --- Ali H. Ataiwi
Journal: KUFA JOURNAL OF ENGINEERING مجلة الكوفة الهندسية ISSN: 25230018 Year: 2018 Volume: 9 Issue: 3 Pages: 17-25
Publisher: University of Kufa جامعة الكوفة

Loading...
Loading...
Abstract

A Jet erosion tester is designed and used to study the relative erosion behavior of high chromium white cast iron (ASTM 532A) at specific concentration of silica sand as an abrasive material, 45° impact angle and two size of abrasive particles. A slurry pot was used which contains two propellers rotated at the speed required for uniform distribution. The test specimens are mounted on test fixture which is fixed and has a provision to move in different angular position to find out the wear for different angles. Two different experiments are conducted preliminarily by using silica sand as abrasive with particle size of 400-600 µm and 600-800 µm. Impact angle of 45° and solid abrasives of 20% wt. concentration are used as fixed parameters for 10 hours. It was found that the erosion resistance decreases with increasing the abrasive particle size.


Article
Studying and Modeling The Effects of Quartz Addition and Heat Treatment on Corrosion Properties of Ceramic Coating

Authors: Ali H. Ataiwi --- Ibtihal A. Mahmood --- Jabbar H. mohmmed
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2011 Volume: 29 Issue: 12 Pages: 2564-2579
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

In this work, a new glass-ceramic coating has been developed and applied, as a single coat without prior chemical treatment of the surface, by using the dipping technique on metal substrate. the coating are designed for application on varies grades of low alloy steel, the selected substrate was low carbon low alloyed steel with (0.2)%C. Various heat treatments at temperatures ( 500,550, and 600˚C ) at different times (60 & 120)min and with quartz addition in the range (0-15)% were used to obtain a glass-ceramics that have the optimum coating properties. These coating have been characterized by x-ray diffraction analyses and the results showed presence of a number of microcrystalline phases which are formed during the heat treatments. The results of corrosion resistance tests indicated that the acid resistance was greatly improved by addition of quartz into enamel frit but at same times decreased the alkali corrosion resistance, while the heat treatments improved both acid and alkali resistance for all cases, this is attributed to the formation of complex network from crystalline phases. The results also indicated that the heat treatment at 600˚C for 120min with 15% quartz addition brought the optimum values for acid resistance property which are improved by 86.66%, while the optimum values for alkali resistance property was brought with free quartz added samples which were treated at 600˚C for 120min. Mathematical modeling is implemented and regression equations are obtained by using ( SPSS ) software to predict the experimental data for acid and alkali corrosion rate. Comparing the predicted and measured values gives high prediction accuracy. The accuracy of prediction has been (82.58%, and 96.7%) for acid and alkali resistance properties respectively.


Article
Effect of Different Coating Techniques with Aluminum on the Corrosion Behavior of Stainless Steel 316L in Seawater

Authors: Ali H. Ataiwi --- Abdul Khaliq F. Hamood --- Rana A. Majed
Journal: Al-Nahrain Journal of Science مجلة النهرين للعلوم ISSN: (print)26635453,(online)26635461 Year: 2012 Volume: 15 Issue: 3 Pages: 112-122
Publisher: Al-Nahrain University جامعة النهرين

Loading...
Loading...
Abstract

This study involves effect of aluminum coating by using different techniques (Aluminizing, Flame spraying, and Hot dipping) on corrosion behavior of stainless steel 316L in seawater. Cathodic and anodic regions are studied by using potentiostat to measure the corrosion parameters through Tafel method which include open circuit potential (Eocp), corrosion potential (Ecorr), and corrosion current density (icorr) in addition to calculation of coating corrosion rates (R). The results indicate that the corrosion rate for coated specimens by aluminizing and flame spraying techniques were less than the values before coating but coating with hot dipping technique gives higher rate than the non coated samples, where the results take the following sequence:Corrosion coating sample < coating sample < coating sampleRate (μm/y) by using pack using flame spray using hot dipping cementation aluminizing The potentials with time were interpreted in order to study the evolution of the film chemistry as it came to equilibrium with solution where the results observed that the aluminum coating by aluminizing reaches to the steady – state faster than other samples. Also the galvanic current density with time were discussed where the results indicates, in general, the transients for specimens show an initial sharp decrease in galvanic current exhibited by all coated specimens followed by a more steady, but erratic decrease in the galvanic current

أن هذه الدراسة تضمنت أثر الطلاء بالألمنيوم باستخدام تقنيات مختلفة (الالمنة، الرش الحراري، التغطيس الساخن) على تصرف التآكل لسبيكة الفولاذ المقاوم للصدأ316L .تم دراسة المناطق الكاثودية والانودية باستخدام المجهاد الساكن لقياس متغيرات التآكل بطريقة تافل، والتي تضمنت جهد الدائرة المفتوحة (Eopc)،جهد التأكل (Ecorr)وكثافة تيار التأكل (icorr) إضافة إلى حسابات معدلات تأكل الطلاء (R).أوضحت النتائج أن معدل التآكل للعينات المطلية بتقنيات الالمنة والرش الحراري حقق قيما أقل من قيمه قبل الطلاء(للعينات غير المطلية)، ولكن الطلاء بتقنية التغطيس الساخن أعطت معدل أعلى حيث ان تسلسل حساب معدل تأكل الطلاء كان كما يلي:معدل التأكل(مايكرومتر/سنة) الطلاء باستخدام > الطلاء باستخدام > الطلاء باستخدام تقنية الالمنة الرش الحراري التغطيس الساخن لقد تم تفسير علاقة الجهود مع الزمن وذلك لدراسة الطبقة المتكونة على السطح في حالة التوازن مع المحلول وقد بينت النتائج ان السطوح المطلية بتقنية الالمنة تصل الى مرحلة التوازن اسرع من النماذج الاخرى المطلية بتقنيتي الرش الحراري والتغطيس الساخن. كما تم دراسة العلاقة بين كثافة التيار مع الزمن واظهرت النتائج عموماً حصول نقصان حاد في التيار يعقبه الوصول الى مرحلة التوازن مع حدوث نقصان شاذ في قيمة التيار ولجميع العينات المطلية.


Article
Effect of Laser Surface Modification on the Corrosion Resistance of Dental Alloys in Artificial Saliva Containing Alcoholic Beverages
تأث رٍ المعاملة السطح ةٍ الل زٍر ةٌ على مقاومة التأكل لسثائك طة الاسىان ف اللعاب الاصطىاع الحاوي على المشروتات الكحول ةٍ

Authors: Ali H. Ataiwi --- Rana A. Majed --- Ali A. Muhsin
Journal: Iraqi Journal of Laser المجلة العراقية لليزر ISSN: 18121195 Year: 2013 Volume: 12 Issue: A Pages: 43-52
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Abstract: The objective of this study is to demonstrate the corrosion behavior of dental alloys Co-Cr-Mo, Ni-Cr-Mo and Ti-Al-V in artificial saliva at pH=4 and 37oC enriched with ethyl alcohol at 8% percentage. The linear and cyclic polarizations were investigated by electrochemical measurements. Laser surface modification was achieved for the three dental alloys to improve corrosion resistance. The results show that corrosion resistance of Co-Cr-Mo and Ni-Cr-Mo alloys only were increased after laser treatment due to the fact that laser radiation has caused a smoother surface, in addition to the decrement in corrosion current densities (icorr) for Co-Cr-Mo and Ni-Cr-Mo alloys and the reverse scan in cyclic polarization became in the wider range of potentials compared with the reverse scan for untreated dental alloys, in addition to the obtainment of smaller hysteresis loop for Ti-Al-V alloy.

الخلاصة هَذف هذا اىجحث اى دراسة سيىك اىحأمو ىثلاثة سجبئل طت الاس بْ ) Co-Cr-Mo, Ni-Cr-Mo, Ti-Al-V ( ف اىيعبة الاصط بْع ع ذْ اص ه ذُروج 4 و 34 درجة ئٍى ةَ واىحبو عي 8% محىه الا ثَب ىّه. ج دراسة الاسحقطبة اىخط واىحيق ثبىطز قَة اىنهزوم بَُُئ ةُ واجز ثَ اى عَب يٍة اىسطح ةُ اىي شُر ةَ ىيسجبئل اىثلاثة ىححس قٍبو ةٍ اىحبمو ف اىيعبة اىحبو عي اى شَزوثبت اىنحىى ةُ. اظهزت اى حْبئج ا قٍبو ةٍ اىحأمو اسدادت ىسج نُة اىنىثيث مزو ىًٍى جُذ ىُّ و سج نُة نُّو مزو ىًٍى جُذ ىُّ فقط - - - -ثعذ اى عَب يٍة اىي شُر ةَ ثسجت الاشعبع اىي شُر اىذ سجت اى عْى ةٍ اىسطح ةُ، ثبلاضبفة اى قّصب مثبفبت ج بُر اىحأمو، وا اى سَحاىعنس ف الاسحقطبة اىحيق اصجح ث ذَي اوسع اىجهذ قٍبر ةّ عٍ الاسحقطبة اىحيق ىيع بُْت غ زُ اى عَب يٍة ثبىي شُر ىيسج نُح الاخ زُج ثبلاضبفة اى قّصب اىحيقة اىهسح زُ ةَ ىسج نُة اىح حُب ىُّ اًى ىَُْ فً بْد ىَ .ً

Keywords


Article
Study Fatigue Behavior of Friction Stir Welded Joints for Dissimilar Aluminum Alloys (2024 -T3 and 7020 -T6)
دراسة سلوك الكلال لوصلات غير متشابهة ملحومة بطريقة الخلط الأحتكاكي من سبائك الألمنيوم (2024 -T3 and 7020 -T6)

Authors: Muna K. Abbass --- Ali H. Ataiwi --- Ahmed Ameed
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2014 Volume: 32 Issue: 2 Part (A) Engineering Pages: 439-452
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

The aim of the present work is to investigate the fatigue behavior of friction stir welded joints for dissimilar aluminum alloys (2024 -T3 and 7020-T6). Friction stir welding (FSW) had been done for 6.6 mm thick plate by using NC milling machine with R18 tool steel of 18mm with shoulder diameter and 6mm pin diameter with different tool designs; threaded cone with double bevel, threaded cylinder with concave shoulder of 4°, and beveled cone with concave shoulder of 4°. FSW were carried out under various welding parameters, travel speed of 40, 50, 75 mm/min, rotation speed range (275-1250) rpm and tilt angle of (Ɵ = 3°) with counterclockwise revolution. Many non- destructive inspections and mechanical tests were performed to evaluate welded joints to determine the best welding parameters. Fatigue test has been done at constant stress amplitude cantilever with stress ratio of (R= -1). The results showed that maximum tensile strength and joint efficiency were 360MPa and 86% respectively for dissimilar joints which were welded at 40mm/min travel speed and 550 rpm rotation speed by using threaded cone with double bevels.

يهدف البحث الى دراسة سلوك الكلال لوصلات غير متشابهة ملحومة بطريقة الخلط الأحتكاكي من سبائك الألمنيوم ((2024 -T3 and 7020-T6 .وأجريت عملية اللحام بالخلط الأحتكاكي لصفئح بسمك 6.6 ملم على ماكنة التفريز المبرمجة باستعمال اداة لحام من فولاذ العدة نوع ( R18 ) وذوكتف قطره 18 ملم ومسمار قطره 6 ملم مع تغيير تصميم الأداة. وقد استعملت ثلاث تصاميم مختلفة للأداة هي مخروط مسنن مشطوف الجانبين, اسطواني مسنن مع كتف مقعر للداخل بزاوية 04 و مخروط مشطوف مع كتف مقعر للداخل بزاوية 4 0 . أجريت عملية اللحام الاحتكاكي عند ظروف لحام مختلفة ، سرع لحام 40 و 50 و75 ملم/دقيقة وسرع دوران ( 275-1250 ) دورة/دقيقة . أجريت عدة فحوصات لا أتلأفية واختبارات ميكانيكية لغرض تقييم وصلات اللحام وتحديد افضل ظروف للحام. أما اختبار الكلال فقد كان من نوع (انحناء دوار) وعند سعة اجهاد ثابت ونسبة اجهاد (R)= -1اظهرت النتائج ان أعظم مقاومة شد للوصلة الملحومة وأعلى كفاءة للوصلة هي 360 ميكاباسكال و 86 % على التعاقب للوصلات غير المتشابهة الملحومة عند سرعة تغذية 40 ملم/ دقيقة وسرعة دوران 550 دورة/ دقيقة باستعمال عُدة مخروطية مسننة مشطوفة الجانبين.


Article
Wear Resistance of a New Glass Ceramic Coating
مقاومة البلى لطلاء سيراميك زجاجي جديد

Authors: Jabbar H. mohmmed --- Ibtihal A. Mahmood --- Ali H. Ataiwi
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2014 Volume: 32 Issue: 6 Part (A) Engineering Pages: 1472-1484
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

A new wear resistance glass-ceramic coating system iron (low alloyed low carbon steel) based substrate was developed. The effects of heat treatment conditions and mill additions on wear resistance of developed coatings resistance were studied. The coating materials showed excellent properties for protection the iron substrate from wear. Also, in this work mathematical modeling is implemented and regression equations are obtained by using ( SPSS ) software to predict the experimental data for wear rate. Comparing the predicted and measured values gives high prediction accuracy.

في هذا البحث تم تطوير طلاء سيراميك زجاجي جديد مقاوم للبلى لمعدن الحديد(فولاذ منخفض السبك منخفض الكاربون) كمادة اساس. تم دراسة متغيرات المعاملة الحرارية زاضافات الطحن على مقاومة البلى للطلاءات المطورة. ابدى الطلاء المستخدم خواص حماية ممتازة لمادة الاساس الحديد ضد البلى. كذلك في هذا البحث تم عمل موديل رياضي وتم الحصول على معادلات انحدار باستخدام برنامج (SPSS) للتنبأ بالبيانات العملية لمعدل الطلاء. اعطت مقارنة النتائج المقاسة بالنتائج المتنبئة دقة تنبأ عالية.

Listing 1 - 10 of 16 << page
of 2
>>
Sort by
Narrow your search

Resource type

article (16)


Language

English (16)


Year
From To Submit

2018 (2)

2016 (1)

2015 (1)

2014 (3)

2013 (2)

More...