Abstract: Hydroxyapatite (HAP) has been coated onto Ti6Al4V and 316L SS substrates by sol-gel method. The coating thicknesses for the analysis were about 40 and 72 μm. Adhesion and corrosion tests have been conducted on uncoated and HAP-coated substrates. The coatings were characterized by XRD, SEM, and adhesion analysis. The corrosion resistance was examined in vitro by potentiodynamic polarization technique in Ringerâs solution at room temperature. Electrochemical analysis indicated that the highest corrosion susceptibility was found on 72-μm-coated 316L SS, and the 40-μm HAP-coated Ti6Al4V showed the highest corrosion resistance. It was observed that the coating thickness was an effective parameter on both adhesion and corrosion resistance. It was shown that adhesion and corrosion resistance decreased with increasing coating thickness on both substrates.
Abstract: In this study, the pitting susceptibilities of AlâCu alloy based metal matrix composites (MMCs) reinforced with boron carbide (B4C) particles have been investigated using cyclic polarization (CP) technique in aerated and deaerated 3.5 wt.% NaCl solution. The effects of reinforcement particle volume fraction and artificially aged (T6) process on corrosion behaviour of the composites have been also examined. It has been found that the 30% B4C MMC is more susceptible to pitting attack compared with 10% B4C MMC.
Abstract: In this study, the corrosion susceptibility of aluminum matrix composites reinforced with artificially oxidized SiO2 and solâgel Fe/TiO2 coated silicon carbide particles (SiCp) has been investigated. Corrosion behavior of the composites, fabricated by the liquid metal infiltration technique, was established in chloride containing alkaline environments by cyclic polarization (CP) and electrochemical impedance spectroscopy (EIS) techniques. It has been found that, solâgel coating of SiC particles with Fe/TiO2 has a detrimental effect on the corrosion characteristics of A380âSiC metal matrix composite.
Abstract: In the present study, the wear behavior of in situ formed Al2O3 reinforced hypereutectic Alâ18Si matrix composite coatings have been investigated. These coatings were successfully fabricated with mechanically alloyed Alâ12Si and SiO2 powder deposited on aluminum substrates by atmospheric plasma spraying (APS). The produced samples were characterized by means of microscopic examinations, hardness measurements and wear tests. The obtained results pointed out that the amount of in situ formed Al2O3 particles increased with increasing spray distance and decreasing in-flight particle velocity and temperature, which was accompanied by an improvement in hardness and wear resistance.
Abstract: The effect of TiC particle volume fraction on the electrochemical behaviours of metal matrix composites (MMCs), which is Al-Cu based reinforced with TiCp has been investigated in both aerated and deaerated 1.0 N HââSOâ aqueous solutions. Composites reinforced with TiC particles at volume fractions of 20, 30 and 40% have been produced by conventional hot pressing method and then, artificially aged (T6). The corrosion susceptibilities of the composites have been analyzed by using the cyclic potentiodynamic polarization technique. The surface morphology of the composites has been determined by scanning electron microscopy (SEM). The results show that the corrosion susceptibilities of the composites increase with increased TiC particle content but decreases with T6 heat treatment performed on the composites.
Abstract: The corrosion mechanisms of the clusters and gas porosities in Al-Si-Mg
based metal matrix composites(MMCs) reinforced with SiC particles were
determined by SEM observations in deaerated 3.5 wt.% NaCl aqueous
solutions. It was found that the composites shown severe pitting behaviors
which could be due to the presence of aggressive Cl ions in the
solution. In addition, SEM observations revealed that corrosion preferentially
started around of cluster and gas porosities and these observations
were correlated with the dissolution mechanisms of aluminium.
Abstract: In this study, the effect of SiC particle volume fraction on the corrosion behavior of Al-Si-Mg based SiCp reinforced metal matrix composites in both aerated and deaerated 3.5 wt.% NaCl aqueous solutions has been investigated. Composites reinforced with 10 and 20 vol.% SiC particles were produced by compocasting technique and then extruded. The corrosion susceptibility was analyzed by measuring the cyclic potentiodynamic polarization. The corrosion rates of the samples were determined by using E-pit, E-corr and i(corr) values obtained from polarization curves. The surface morphology of the composites was determined by an optical microscopy and scanning electron microscopy (SEM). In addition, X-ray diffraction (XRD) technique has been used in order to determine the phases occurring at the matrix/SiC interface. The obtained results indicate that the corrosion resistance of the composites decreased with increased SiC particle content.
Abstract: Günümüzde iÅ makinalarında gürültü problemi iki Åekilde ortaya çıkmaktadır, birincisi iÅi makinaları içinde bulunan operatörün maruz kaldıÄı gürültü, ikincisi de bu araçlardan dolayı oluÅan çevresel gürültüdür. Bu öngörüler doÄrultusunda bu çalıÅmada iÅ makinaları üzerinde oluÅan gürültü problemi ele alınmıÅ, bu amaçla ülkemizde faaliyet gösteren çeÅitli kamu ve özel sektör kuruluÅlarında yol ve bina yapımında kullanılan iÅ makinalarının çalıÅma ortamlarındaki gürültü düzeylerinin ölçümü ve bu deÄerlerinin Åu an yürürlükte olan âGürültü Kontrol YönetmeliÄiâ ile belirlenen ve insan saÄlıÄı açısından istenilen sınırlarda olup olmadıÄını araÅtırmak, olabilecek çözüm yollarını ortaya koymak ve konunun önemini vurgulamaktır.
Abstract: The influence of age hardening on the corrosion behavior of Al-Si-Mg-based metal matrix composites (MMCs) has been investigated in aerated and deaerated 3.5 wt% aqueous NaCl solutions. Silicon carbide particle (SiCp) reinforced composites consisting of 10 and 20 vol% SiC(p)s are produced by the compocasting technique. After the extrusion process, the composites are artificially aged (T6). The corrosion resistances of the aged composites are analyzed by measuring the cyclic potentiodynamic polarization. The surface morphology of the composites before and after the corrosion tests are determined by using metallographic methods and scanning electron microscopy (SEM). In addition, the X-ray diffraction technique (XRD) has been used to determine the phases that occur at the matrix-reinforcement interface. The results demonstrate that the E-pit values of unreinforced matrix alloy and composites increase negatively with increasing aging time. It is also observed that corrosion preferentially starts at the interface of Al-Mg2Si and Al-SiCp.
Abstract: Magnezyum ve alaÅımlarının mekanik özellikleri otomotivdeki birçok uygulamaya elveriÅlidir. Mg sahip olduÄu 1.74g/cm3âlük özkütlesi ile yapısal malzemelerin en hafiflerinden biridir ve diÄer hafif metallere göre daha iyi mekanik özelliklere sahiptir. Ä°yi mekanik özelliklerine raÄmen elektrokimyasal olarak oldukça aktif bir metal olması magnezyumun niçin hala Al alaÅımları kadar popüler olmamasının nedenlerinden biridir. Bu durum magnezyum alaÅımlarının endüstride yaygın bir Åekilde kullanımını sınırlandıran etmenlerin de baÅında gelmektedir. Bu çalıÅmada, çift merdaneli sürekli döküm tekniÄi ile 4,5 mm kalınlıÄında üretilen AZ31 magnezyum alaÅımı levhalara uygulanan homojenizasyon ısıl iÅlemi sonrası korozyon hassasiyetleri belirlenmeye çalıÅılmıÅtır.
Abstract: Ãzellikle uzay, otomotiv ve savunma sanayileri gibi endüstri kollarında daha iyi performansa ulaÅmak için yeni mühendislik malzemelerine ihtiyaç duyulmuÅ ve bu talep metal matriksli nano kompozit (MMNK) malzemelerin geliÅtirilmesine neden olmuÅtur. Ä°kinci nesil metal matriksli kompozitler (MMK) olarak da bilinen bu malzemelerin günümüzde metal ve diÄer malzemelere alternatif hale gelmelerinin baÅlıca nedenleri; sahip oldukları yüksek tokluk ve rijitlik nedeniyle iyi aÅınma direnci ve üstün yorulma dayanımı sergilemeleridir. Inâsitu takviyeli kompozit malzemeler kuvvetlendirici fazların üretim esnasında kimyasal reaksiyonlarla matriks bünyesinde sentezlendiÄi çok fazlı malzemelerdir. Bu çalıÅmada, AlâCu/Al2O3 inâsitu kompozitlerin konvansiyonel sıcak presleme yöntemiyle üretilmesi esnasında sinterleme süresinin etkisi araÅtırılmıÅtır. Bu amaçla 1000°Câde dört farklı sinterleme süresinde kompozitler sentezlenmiÅ ve bunların sertlik, mikroyapı ve arayüzey özellikleri incelenmiÅtir. Kompozitlerin karakterizasyonu XâıÅınları difraktometre (XRD) cihazı ve taramalı elektron mikroskobu (SEM) ile yapılmıÅtır. Mekanik özellikler ise, makro ve mikro sertlik ölçme yöntemleri ile açıÄa çıkarılmıÅtır.
Abstract: In this study, corrosion and mechanical properties of in situ Al based metal matrix composites prepared from the Al-TiO2 and Al-TiO2-C systems via hot pressing were investigated. Microstructural characterizations of the composites were made by microscopic examinations. Corrosion resistance of the composites was analyzed by using the potentiodynamic polarization scanning technigue. Room temperature mechanical properties of the composites were determined by hardness measurements and wear tests. Microstructural examination revealed that Al2O3 particles and Al3Ti plates were in situ formed in Al-TiO2 and Al-TiO2-C systems, respectively. Among the composites examined, the Al-TiO2-C system exhibited the highest hardness, wear and corrosion resistance, while lowering the friction coefficient.
Abstract: In-situ metal matrix nanocomposites (MMNC) are multiphase materials whose reinforcing phases are synthesized in the matrix by chemical reactions during fabrication. In this study, Al based composite reinforced with in-situ TiC nano particles was produced by conventional hot pressing. The microstructural and interfacial properties of the produced composite were investigated. The equipments were used, are differential thermal analysis (DTA) to figure out the formation reactions during sintering process and X-ray diffractometry (XRD) to obtain the phases. In addition, scanning electron microscope (SEM) and transmission electron microscope (TEM) were be used to examine the in-situ phase structures in the nanocomposites.
Abstract: In this study, corrosion properties of NiTi powder mixture alloyed on austenitic stainless steel (AISI304) surface by plasma transfer arc (PTA) method have been investigated. Surface alloying process is turned out using 80, 90, 100 A current densities and Ar atmosphere which is plasma and protective. The corrosion characteristics of surface alloyed specimens were determined with potentiodynamic polarization technique. After polarization tests, the specimens were examined using scanning electron microscope (SEM).
Abstract: In the present study, corrosion resistance of an in-situ Al/TiC nanocomposite produced by conventional hot pressing method has been examined in deaerated 0.1M NaCl solution at room temperature. 80wt.% Al, 16wt.% Ti and 4wt.% C powders was mixed to obtain an Al based composite reinforced with in-situ nano TiC particles. The corrosion susceptibility of Al/TiC nanocomposite has been examined using potentiodynamic polarization technique. Characterization studies of the composite were carried out by scanning electron microscope (SEM) and X-ray diffractometer (XRD). It has been found that the nanocomposite shows decreased susceptibility to pitting attack compared with unreinforced pure-Al.
Abstract: Until very recently, the most commonly used methods in industry to prevent corrosion have been the pre-passivation processes such as chromate conversion coating and phosphating. These processes have recently been proved to be harmful for the environment and banned by many local governments. The extensive research on the high performance raw materials with high environmental stability shows that the conjugate-heterocyclic organic molecules and their advancing polymer applications can be an attractive alternative of chromate conversion coating and phosphating. The aim of this study is to investigate the effects of polypyrol primer applications on under-paint corrosion in steels and compare the effectiveness of this method with some other applications. In the experiments, polypyrol coatings are applied practically on the mild steel surfaces. Some of these samples are painted with water-based paints whereas some others are painted by epoxy paints. Another set of samples are prepared by applying paints with pyrol additives on the steel sheets that are not processes prior to coating. The prepared samples are mechanically eroded and have been exposed to nondestructive electrochemical tests for 5 days in a chloride medium. The process flow is concluded with excessive polarization experiments. The results of different electrochemical tests agree on the fact that in prevention of corrosion, the ppy coatings underneath the epoxy paints are more effective compared to phosphating and the other techniques examined within the scope of this study.
Abstract: In-situ plasma spraying (IPS) is a promising process to fabricate composite coatings with in-situ formed thermodynamically stable phases. In the present study, mechanically alloyed Alâ12Si and SiO2 powder was deposited onto an aluminum substrate by atmospheric plasma spraying (APS) to obtain a composite coating consist of in-situ formed alumina reinforced hypereutectic Al-18Si matrix alloy. The effect of gun current of plasma spraying on the corrosion behavior of the composite coating has been investigated. The corrosion resistances of the composite coatings were analyzed by measuring the cyclic potentiodynamic polarization technique. The surface morphology of composite coatings before and after corrosion tests were determined by using metallographic methods and scanning electron microscopy (SEM). Obtained results are discussed in detail.
Abstract: Günümüzde, metal matrisli kompozitlerin (MMK) üretimi için deÄiÅik toz karıÅtırma, döküm, infiltrasyon veya toz metalürjisi yöntemleri kullanılmaktadır, ancak bu metotlarla yüksek takviye oranlı MMK üretimi oldukça sınırlıdır. Ayrıca kullanılan takviye türü ile kompozitin; yoÄunluk, mukavemet, elastik ve plastik özellikleri deÄiÅtirilebilir. Ãünkü kullanılan kuvvetlendiricinin matrisle uyumlu ve kararlı bir arayüzey oluÅturması oldukça güçtür. Bu çalıÅmada MMK üretiminde sıkça kullanılan iki farklı kuvvetlendirici partikülün (SiCp ve TiCp) yüksek oranlarda (%40) 2xxx serisi alüminyum matris alaÅımına takviyesi durumunda kompozitin elektrokimyasal davranıÅı üzerinde oluÅan deÄiÅimler araÅtırılmıÅtır. Kompozitler sıcak presleme (hot pressing) yöntemi ile üretilmiÅ olup, elektrokimyasal duyarlılıkları potansiyodinamik polarizasyon ve elektrokimyasal empedans spektroskopi (EIS) teknikleri yardımıyla belirlenmiÅtir. Metalografik incelemeler SEM ve optik mikroskop kullanılarak gerçekleÅtirildi. Elde edilen verilerden, SiC katkılı kompozitin hem ara yüzey özelliklerinin hem de polarizasyon direncinin daha iyi olduÄu görülmüÅtür.
Abstract: Günümüzde teknolojinin ilerlemesine paralel olarak otomotiv, havacılık, savunma gibi endüstri alanlarında kullanılacak üstün nitelikli malzeme istemi de artmaktadır. Kompozit malzemeler üretimde bu boÅluÄu doldurmaya yönelik geliÅtirilen malzeme gruplarındandır. Kompozitlerin parçacık takviyeli olanları ise, fiber takviyeli olanlara göre daha düÅük maliyete ve daha iyi bir rijitliÄe sahiptirler. Ayrıca, partikül takviyeli metal matris kompozitler (MMKâlar) tam olarak izotropikte kabul edilmektedirler. MMKâlar özellikle yüksek sıcaklık ve korozyon dayanımı istenen, silindir blokları, silindir kapaÄı, pistonlar ve valflerin üretiminde geniÅ bir kullanım alanı bulurlar. Bu çalıÅmada %35â40 oranında SiC partiküller (SiCp) ile kuvvetlendirilmiÅ AlâCu alaÅımlarının elektrokimyasal davranıÅları hem normal atmosfer Åartları altında hem de N2 atmosferi altında bulunan çözelti Åartlarında incelenmiÅtir. ÃalıÅma bu tip kompozitlerde SiCp oranı artımıyla kompozitlerin korozyon duyarlılıklarının arttıÄını göstermiÅtir.
Abstract: Bu çalıÅmada, nikel kaplanmıŠfarklı malzemelerin korozyon davranıÅları karÅılaÅtırıldı. Bu amaçla, bir pirinç alaÅımı (CuZn30) ve bir çelik (AISI 1020) malzeme üzerine elektrolitik yöntemle nikel kaplandı. KaplanmamıŠve nikel kaplanmıŠtaban malzemelerin korozyon davranıÅları polarizasyon ve impedans teknikleri ile belirlendi. Kaplamaların yapısal özellikleri X-ıÅını difraksiyonu (XRD) kullanılarak karakterize edildi. Kaplamaların yüzey morfolojisi taramalı elektron mikroskobu (SEM) ile incelendi. Numunelerin yüzey sertlikleri Vickers sertlik testi ile tayin edildi. Yapılan nikel kaplamaların hem pirinç ve hem de çelik taban malzemelerin korozyon direncini artırdıÄı ve farklı taban malzeme kullanımının korozyon direncindeki artıŠmiktarını etkilediÄi belirlendi. Ayrıca, her iki taban malzemenin sertliÄinin de yapılan nikel kaplamalarla önemli miktarda arttıÄı gözlendi.
Abstract: The corrosion behaviors of T8 tempered AlâSiâMg/SiCp metal matrix composites (MMCs) were investigated in aerated and deaerated 3.5wt% NaCl solutions by potentiodynamic polarization technique in this study. In order to determine the effect of cold work on the electrochemical behavior, the composites were cold-worked to a plastic strain of 4, 6, 10, 25 and 50%. A major change in the corrosion morphologies were observed cold working ratio increased from 4 to 50%. For example, electrochemical analysis indicated that the corrosion current densities (icor) of 20% vol. SiC composite increased from 0.8 to 5.9 with increasing cold-worked ratio after T8 temper. In addition, we find that there is a significant coloration between corrosion susceptibility and level of cold work.
Abstract: In this study, the pitting susceptibility of Al-Cu alloy based metal matrix composites (MMCs) reinforced with particulate boron carbide (B4C) has been examined using potentiodynamic polarization technique in deaerated 3.5wt% NaCl solutions at room temperature. The composites consisting are produced by the conventional hot pressing technique. Also, it has been investigated the effects of reinforcement particle volume fraction and voids in the composites. Optical microscopy and scanning electron microscope (SEM) metallographic studies were carried out on the samples. It has been found that the 30% B4C MMC is more susceptible to pitting attack compared with 10% B4C MMC.
Abstract: In this study, the effect of TiC particle volume fraction on the electrochemical behaviors of AlâCu based TiCp reinforced metal matrix composites (MMCs) in both aerated and deaerated 1.0 N H2SO4 aqueous solutions has been investigated. Composites reinforced with TiC particles at volume ratios 20 to 40% were produced by conventional hot pressing method and then artificially aged (T6). The electrochemical susceptibilities of the composites were analyzed by using the cyclic potentiodynamic polarization technique. The corrosion rates of the samples were determined by using Epit, Ecorr and icorr values obtained from polarization curves. The surface morphology of the composites was determined by a scanning electron microscopy (SEM). 1. The results show that the TiCp and its volume fraction have a great effect on the electrochemical behaviors of the composites.
Abstract: Günümüzde iÅ makinalarında gürültü problemi iki Åekilde ortaya çıkmaktadır, birincisi iÅi makinaları içinde bulunan operatörün maruz kaldıÄı gürültü, ikincisi de bu araçlardan dolayı oluÅan çevresel gürültüdür. Bu öngörüler doÄrultusunda bu çalıÅmada iÅ makinaları üzerinde oluÅan gürültü problemi ele alınmıÅ, bu amaçla ülkemizde faaliyet gösteren çeÅitli kamu ve özel sektör kuruluÅlarında yol ve bina yapımında kullanılan iÅ makinalarının çalıÅma ortamlarındaki gürültü düzeylerinin ölçümü ve bu deÄerlerinin Åu an yürürlükte olan âGürültü Kontrol YönetmeliÄiâ ile belirlenen ve insan saÄlıÄı açısından istenilen sınırlarda olup olmadıÄını araÅtırmak, olabilecek çözüm yollarını ortaya koymak ve konunun önemini vurgulamaktır.
Abstract: Günümüzde teknolojinin ilerlemesine paralel olarak malzemelerden istenen özellikler de deÄiÅmektedir. Metal matrisli kompozitler diÄer malzemelere göre daha düÅük maliyete ve daha fazla rijitliÄe sahiptirler. Döküm yöntemiyle de üretilebilen bu kompozitler, üretim aÅamasında ortaya çıkan yüksek porozite miktarları nedeniyle kullanımları sınırlanmaktadır. Literatürde bu porozitelerin tipleri ve kompozitin mekanik özellikleri üzerine etkileri ile ilgili bir çok çalıÅma mevcuttur ancak bu etkilerin korozyon açısından incelenmesi yok denecek kadar azdır. Al/SiC kompozitlerde porozite, SiC parçacıkların matris alaÅımına katılması sırasında belli bölgelerde topaklanması, Al/SiC arayüzeyindeki adhezyon eksikliÄi, ergimiÅ matrise difüze olan gazlar veya üretim sonrası uygulanan ısıl iÅlemler sonucunda meydana gelen hacim daralmaları nedeniyle oluÅabilir. Sonuçta, porozitelerin oluÅtuÄu bölgelerde kompozitin elektrokimyasal aktiviteleri deÄiÅir ve korozyon karakteristikleri farklılaÅmaya baÅlar. Bu çalıÅmada karıÅtırmalı döküm ve ekstrüzyon yöntemleri ile üretilen Al-Si-Mg matrisli kompozitlerde görülen porozite tiplerinin korozyon karakteristiÄi üzerine etkisi incelenmiÅtir.
Abstract: TaÅımada kullanılan kaynakla birleÅtirilmiÅ borular çevreye açık olarak kullanılmaları nedeniyle hem malzeme farklılıÄı hem de aktif çevrenin etkisiyle korozyon ve gerilmeli korozyondan kaynaklanan hasarlarla karÅı karÅıyadırlar. Bu çalıÅmada Fe-37 düÅük karbonlu alaÅımsız çeliÄin, toz altı kaynak yöntemiyle birleÅtirilmesi ve 500 ila 700oCâler arasında çeÅitli sıcaklıklarda tavlanması sonucunda elde edilen numunelerin, 0,1M Na2SO4 çözeltisindeki korozyon davranıÅı incelenmiÅtir. ÃalıÅmada kullanılan malzemelerin yapısal özelliklerini belirlemek için; mikro sertlik cihazı, optik mikroskop, lineer polarizasyon ölçme yöntemi, alternatif akım empedans yöntemi ve SEM (Scanning Electron Microscopy) kullanılmıÅtır. ÃalıÅma sonunda, esas metalin 500oC, ITABâın (Isı Tesiri Altındaki Bölge) 700oC ve kaynak bölgesinin 650oCâde yapılan tavlamalarının en yüksek polarizasyon direncine sahip olduÄu bulunmuÅtur. Ayrıca, en iyi korozyon direncine sahip kaynak birleÅtirmesi elde edilebilmek için, 500oC sıcaklıkta yapılacak tavlama iÅleminin yeterli olduÄu bulunmuÅtur.
Abstract: The production and potential applications of metal matrix composites have been dramatically increased with technological developments since 20 years. Compared to metallic alloys, ceramic particulate reinforced metal matrix composites (MMCs) own improved mechanical properties. One of the most widespread ceramic-metal combinations for MMCs is SiC/Al system. Although extensive investigations have been carried out on the mechanical properties of aluminum-based metal matrix composites (AMMCs), the corrosion behavior of these composites are still incomplete. This problem is one of the main drawbacks to the widespread use of MMCs in engineering applications. In this study, the corrosion behaviour of AMMCs was investigated.
Abstract: Ä°Å makineleri, fonksiyonları gereÄi aÄır koÅullarda çalıÅmaktadırlar. ÃalıÅma koÅulları ve çevre ile temasta olan parçaların hem mekanik hem de elektrokimyasal özellikleri oluÅan reaksiyona baÄlı olarak zamanla deÄiÅmektedir. Ãevreye açık ortamlarda çalıÅan tüm makine parçalarında korozyon ve yeterli bakımın saÄlanamadıÄı koÅullarda aÅınma mekanizmaları nedeniyle büyük oranlarda malzeme kaybı olmaktadır. Sürtünmenin ve çevrenin etkisini azaltmak amacıyla, bakım amaçlı yapılan yaÄlama iÅlemi çalıÅma koÅullarına baÄlı olarak toz partiküllerle birleÅmesi sonucu aÅındırıcı görevini üstlenmekte ve iÅ makinelerinin çalıÅan bir çok parçasına fayda yerine zarar vermektedir. Bu araÅtırmada, iÅ makinelerinin özellikle yürüyüŠtakımları üzerine çalıÅma koÅulları ve çevrenin etkisiyle oluÅan hasarlar irdelenecektir.
Abstract: In this study, corrosion behaviours were investigated of metal matrix composites (MMCs) based Al-7%Si-0.7%Mg reinforced with SiC particles 10, 20 vol.% respectively. Cyclic potentiodynamic polarization tests have been carried out to assess the effects reinforcement particle volume fraction, reactions product at the particle/matrix interface and voids at the interface on corrosion characteristics of both matrix alloy and composites in 3.5 wt.% NaCl aqueous solution, and then, the corrosion behaviour of composites was determined by using Epit, Ecorr and icorr values obtained from polarization curves. In addition, the effect of ageing heat treatment (T6) on the corrosion behaviour of composites was investigated. The surface morphology of composites before and after corrosion test was determined by an optical microscopy and SEM, also, XRD technique has been used in order to determine intermetalic phases occurred at the matrix/SiC interface. The end of the study, it has been found that pitting corrosion was the primary type of attack, and the corrosion resistance decreased with increased both SiC particle volume fraction and ageing time in Al/SiC composites.
Abstract: Compared to traditional metal matrix composites (MMC), in-situ metal matrix nanocomposites (MMNCs) own improved mechanical properties. MMNC is a multiphase material whose reinforcing phases are synthesized in the matrix by chemical reactions during fabrication. In the literature, the studies on production process, mechanical and corrosive properties of these composites are relatively rare. In this study, Al based composite reinforced with in-situ TiC nano particles was produced by conventional hot pressing. The microstructural, interfacial, mechanical properties and corrosive behavior of the produced composite were investigated. These tests indicated that Al matrix reinforced with in-situ TiC nano particles improved the hardness, strength and corrosion resistance. The equipments were used, are differential thermal analysis (DTA) to figure out the formation reactions during sintering process, X-ray diffractometry (XRD) to obtain the phases and potentiostat system to examine the corrosive behaviors. In addition, scanning electron microscope (SEM) and transmission electron microscope (TEM) were be used to examine the in-situ phase structures in the nanocomposites.
