Papers by Mehdi Akbarifar
In this article, interface characteristics of aluminum and cast iron bimetal has been investigate... more In this article, interface characteristics of aluminum and cast iron bimetal has been investigated. To reach an acceptable composite products, from two materials, interface characteristics needs to be investigated. C, around cylindrical cast iron bars having melt/solid volume ratios of 3, 5 and 8, respectively. Optical and SEM microscopic observations showed that a reaction layer may form at the interface. This layer is composed of Fe2Al5 intermetallic which forms initially at the rough surface of the insert after making contact with molten metal. Microstructural analysis showed the increasing of temperature and the Vm/Vs ratio leads to formation of a thicker and more uniform intermetallic layer. Microhardness of the Fe2Al5 HV V V C and 8 Vm/Vs. A mechanism is suggested for nucleation and growth of this intermetallic layer and also graphite engulfment of gray cast iron, by aluminum melt, at the interface of two metals.
International Journal of Metalcasting
Journal of Mining and Metallurgy, Section B: Metallurgy, 2017
The interface characteristics of aluminum/cast iron bimetals produced by compound casting were in... more The interface characteristics of aluminum/cast iron bimetals produced by compound casting were investigated. Aluminum melt was poured into molds, at 700?C and 750?C, around cylindrical cast iron bars having melt-to-solid volume ratios (Vm/Vs) of 3, 5 and 8, respectively. Microscopic observations showed that a reaction layer may form at the interface. This layer is composed of Fe2Al5 intermetallic which has been formed initially at the notches of the insert?s surface after making contact with the molten metal. The thickness of the interaction layer varied from 5?m, for the sample produced at 700?C and 3 Vm/Vs, up to 20?m for the sample poured at 750?C and 8 Vm/Vs. Microstructural analysis showed that increasing of the temperature and the melt-to-solid (m/s) volume ratio leads to the formation of a thicker and more uniform intermetallic layer. Microhardness of the Fe2Al5 compound was measured 824 HV. A mechanism is suggested for the nucleation and growth of this intermetallic layer an...
International Journal of Metalcasting, 2022
Journal of Magnesium and Alloys, 2021
Abstract The dynamic oxidation of molten Mg–Al alloy was investigated via the oxide /metal/oxide ... more Abstract The dynamic oxidation of molten Mg–Al alloy was investigated via the oxide /metal/oxide (OMO) sandwich method. The characteristics of sandwiches were explored using optical microscopy, scanning electron microscopy, X-ray energy dispersive spectroscopy, and X-ray diffraction analyses. The results showed the formation of porous oxide films with varying thicknesses from 0.43 to 16.7 mm. Both the measurements and calculations confirmed the literature findings that the oxidation product consists mainly of MgO and MgAl2O4 compounds. The increase in thickness and amount of folds formed on the oxide films implies the significant effect of aluminum in reducing the oxidation resistance of magnesium.
Izvestiia Akademii nauk SSSR. Seriia biologicheskaia
International Journal of Metalcasting, Jul 1, 2017
Your article is protected by copyright and all rights are held exclusively by American Foundry So... more Your article is protected by copyright and all rights are held exclusively by American Foundry Society. This e-offprint is for personal use only and shall not be self-archived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".
Journal of Magnesium and Alloys, Mar 1, 2020
International Journal of Metalcasting
International Journal of Metalcasting, 2016
International Journal of Cast Metals Research, 2012
ABSTRACT Nowadays, active-screen plasma nitriding method is going to become a widely used nitridi... more ABSTRACT Nowadays, active-screen plasma nitriding method is going to become a widely used nitriding process due to some advantages, e.g. elimination of work piece edge effects of glow discharge. To investigate possibility of non-ferrous alloys nitriding by the use of this process, corrosion properties of AA 2024 aluminum alloy after active-screen and conventional plasma nitriding at 400, 450 and 500ºC temperatures, 10 hours process time and 25%H2-75%N2 containing atmosphere were studied. The screen was made of the commercial pure aluminum. Scanning electron microscopy results showed that a uniform AlN layer is formed on the surface of all samples. In lower temperatures nitride particles were grown on the surface, but by increasing the process temperature, these nitrides disappeared and a uniform layer was formed. Also, X-ray diffraction analysis confirmed the formation of AlN on the surface. Polarization tests were conducted in 3.5% NaCl solution. Results showed improvement in corrosion resistance after both active-screen and conventional plasma nitriding.
An investigation has been conducted to study interface characterization of Al/Cast Iron bimetals ... more An investigation has been conducted to study interface characterization of Al/Cast Iron bimetals produced by compound casting. Aluminum melt with 700 and 750 C temperatures was poured around cylindrical cast iron inserts by 3, 5 and 8 Melt/Insert volume ratios. Optical microscope and scanning electron microscope observations showed that a diffusion layer is formed at interface. XRD analysis proved that the interface layer is composed of Fe 2 Al 5 intermetallic. Increasing the pouring temperature and the V m /V s volume ratio formed more uniform and thicker intermetallic layer. Microhardness test showed 824 HV for Fe 2 Al 5 .The thickness if this layer varies from 5µm particles of sample produced in 700 C and 3 V m /V s to 19.74µ in sample which made at 750 C and 8 V m /V s .
با توجه به گسترش استفاده از فیبرهای کربن در صنعت ، به دلیل خصوصیاتی چون چگالی کم و استحکام بالا ،... more با توجه به گسترش استفاده از فیبرهای کربن در صنعت ، به دلیل خصوصیاتی چون چگالی کم و استحکام بالا ، مطالعه ی رفتار شکست کامپوزیت های تقویت شده با الیاف کربن امری ضروری به نظر می رسد.با بررسی تحقیقات انجام گرفته بر رو رفتار شکست کامپوزیت های تقویت شده با الیاف کربن ، به این نتیجه می رسیم که رفتار شکست کامپوزیت متاثر از رفتار شکست هر دو جزء سازنده ی آن و همینطور برهمکنش دو جزء در فصل مشترک فیبر/ماتریس است. از این رو تحقیقاتی بررسی شده اند که رفتار شکست فیبر ، تاثیر نرخ سرمایش بر استحکام ماتریس ، رفتار شکست کامپوزیت تقویت شده با الیاف کربن وهمینطور تاثیر تقویت سازی بر کرنش های بوجود آمده رامطالعه کرده اند. نتیجه گیری ها عمدتا بر اساس محاسبه ی K_Ic ، K_IIc ، G_Ic و G_IIc بوده اند.شرح مختصری بر تئوری آزمایشات در هر قسمت آورده شده است.تاثیر مثبت تقویت سازی با الیاف کربن در تمام موارد اثبات شده است.
ریخته گری مرکب فرآیندی است که جهت تولید دو فلزی های مختلف به کار می رود. در این فرآیند جامد یک فل... more ریخته گری مرکب فرآیندی است که جهت تولید دو فلزی های مختلف به کار می رود. در این فرآیند جامد یک فلز داخل قالب قرار گرفته و مذاب فلز دوم داخل قالب ریخته گری می گردد. این مقاله به بررسی فصل مشترک بوجود آمده در دوفلزی آلومینیم/برنج طی فرایند ریخته گری مرکب اختصاص دارد. مذاب آلومینیم خالص در دو نسبت حجمی مختلف 3 و 5 و دماهای بارریزی متفاوت 700 و 750 درجه سلسیوس، گرد هسته ی برنجی ریخته شده است. اندرکنش مذاب و جامد ،تشکیل یک ناحیه ی نفوذی و متعاقب آن یک لایه ی انتقالی پیوسته منجر به ایجاد لایه های بین فلزی در فصل مشترک دو فلز می گردد. نتایج بررسی های میکروسکوپی و آزمایشات اشعه ایکس حاکی از تفاوت ضخامت و ماهیت لایه های بین فلزی در فصل مشترک دو فلز است به گونه ای که افزایش انرژی حرارتی در دسترس سبب تشکیل لایه های با ضخامت بیشتر در فصل مشترک شده است. لایه های بوجود آمده در فصل مشترک . به ترتیب از سمت مغزهی برنجی عبارتاند از سه لایهی ترکیب بین فلزی CuZn، Al4Cu3Zn، Al2Cu ، لایهی یوتکتیک α-Al/Al2Cu و در نهایت لایهی دندریت + یوتکتیک. بیشترین سختی برای سه لایه ترکیبات بین فلزی در فصل مشترک، ب...
An investigation has been conducted to study interface characterization of Al/Cast Iron bi-metals... more An investigation has been conducted to study interface characterization of Al/Cast Iron bi-metals produced by compound casting. Aluminum melt with 700 and 750 ̊ C temperatures was poured around cylindrical cast iron inserts by 3, 5 and 8 Melt/Insert volume ratios. Optical microscope and scanning electron microscope observations showed that a diffusion layer is formed at interface. XRD analysis proved that the interface layer is composed of Fe 2 Al 5 intermetallic. Increasing the pouring temperature and the V m /V s volume ratio formed more uniform and thicker intermetallic layer. Microhardness test showed 824 HV for Fe 2 Al 5 .The thickness if this layer varies from 5µm particles of sample produced in 700 ̊ C and 3 V m /V s to 19.74µ in sample which made at 750 ̊ C and 8 V m /V s .
ریخته گری مرکب فرآیندی است متالورژیکی که جهت تولید دو فلزی های مختلف به کار می رود و از جنبه ی قد... more ریخته گری مرکب فرآیندی است متالورژیکی که جهت تولید دو فلزی های مختلف به کار می رود و از جنبه ی قدرت تولید دوفلزی هایی با شکل های پیچیده و در اندازه ی بزرگ بر بسیاری از روش های اتصال دوفلز برتری دارد. در این فرآیند جامد یک فلز داخل قالب قرار گرفته و مذاب فلز دوم پیرامون آن ریخته گری می گردد. این مقاله به بررسی فصل مشترک بوجود آمده در دوفلزی آلومینیم/برنج طی فرایند ریخته گری مرکب اختصاص دارد. مذاب آلومینیم خالص در دو نسبت حجمی مختلف 3 و 5 و دماهای بارریزی متفاوت 700 و 750 درجه سلسیوس، گرد هسته ی برنجی ریخته شده است. اندرکنش مذاب و جامد ، با تشکیل یک ناحیه ی نفوذی و متعاقب آن یک لایه ی انتقالی پیوسته منجر به ایجاد لایه های بین فلزی در فصل مشترک دو فلز می گردد. نتایج بررسی های میکروسکوپی و آزمایشات اشعه ایکس حاکی از تفاوت ضخامت و ماهیت لایه های بین فلزی در فصل مشترک دو فلز است به گونه ای که افزایش انرژی حرارتی در دسترس سبب ایجاد لایه های ضخیم تر و بیشتری می شود. . این لایه های به ترتیب از سمت مغزهی برنجی عبارتاند از سه لایهی ترکیب بین فلزی CuZn، Al4Cu3Zn، Al2Cu ، لایهی یوتکتیک α-Al/...
Aluminum 2XXX series are used extensively in automotive and aerospace applications due to their h... more Aluminum 2XXX series are used extensively in automotive and aerospace applications due to their high strength/weight ratio. However the usage in corrosive environments is limited due to their Corrosion susceptibility .Effects of precipitates and metallurgical processes on corrosion resistance was evaluated. Precipitation of intermetallic compounds and their potential differences with the surrounding renders the alloy susceptible to pitting corrosion. Electrochemical behavior of Mg changes corresponding to the surrounding matrix, and in could be anodic,cathidic or protective.Mg,the active metal,forms intermetallic compound of Al2CuMg (S phase).It has a high corrosion rate and acts as the sacrificed anode due to its lower electro potential in contrast with Cu and Al.Pitting and formation of micro galvanic cells is exhibited. With the depletion of Mg, S phase turns to cathode and surrounding matrix is corroded Corresponding to the depletion of Mg.Al8Mg5 is reported to be a protective l...
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Papers by Mehdi Akbarifar