In this study, the nano MgO particles and multi-walled carbon nano tubes (MWCNTs) are inserted into AlSi10Mg matrix, and the composites are produced via selective laser melting (SLM) method. The composite comprises of AlSi10Mg, and mixing of 0.005 wt.%, 0.010 wt.%, and 0.020 wt.% of MgO and MWCNTs. The microstructure of the SLMed composites is examined with optical and scanning electron microscope. It is revealed that intermetalics and the supersaturated primary α-Al structure which increases the strain hardening, surrounded by interconnecting fibrous Si phase which then were transformed to a coarse eutectic structure that tends to be less stiff. The mechanical behaviors are analyzed by tensile, hardness and nanoindentation tests, finally the fracture surfaces of the used specimens are studied via scanning electron microscope (SEM). The tensile strength value of the SLMed AlSi10Mg materials increased from 405 to 559 MPa. Best strength-ductility pattern with maximum tensile strength (559 MPa), yield strength (253 MPa) and elongation (5.9%) is obtained, that is comparable and superior to the Alsi10Mg alloy. The tensile test fracture surfaces of the composites showed a clear mode of the ductile fracture. Additionally, the hardness of AlSi10Mg alloy rose from 85 to 137 HV. In the nanoindentation test, Doerner and Nix, Oliver and Pharr, and Suresh models for hardness were used. Among the three models, the lower error percentage was seen in the Suresh model which contributed to obtaining the best results. Young’s modulus of AlSi10Mg improved by 3.39%, 8.97%, and 12.93% with reinforcement content of 0.005 wt.%, 0.010 wt.%, and 0.020 wt.%, respectively.

In this work, the Al–xMg–MgO composites were fabricated via stir casting method. The different amounts of Mg (1, 3 and 5 wt

In this research, the aluminum (Al2024) matrix composites are reinforced with nano magnesium oxide (MgO) and multi-walled carbon nanotubes (MWCNTs). The aim of Al2024 alloy reinforced with MgO and MWCNTs is to reveal the effects of the reinforcement particle ratio on the microstructure and mechanical properties of the hybrid composites, to find the optimum hybrid ratio, and to form a stronger hybrid composite. The composites with the different hybrid ratios are produced via stir casting method. The theoretical and measured densities and porosity content of the composites are studied. The microstructure and fracture surface of the composites are examined by optical microscopy, scanning electron microscopy (SEM), and electron dispersive spectrum (EDS). The hardness, compression, and tensile properties of the composites are studied in this work. Results indicated that the hardness of the aluminum (Al) matrix composites (AMCs) is significantly improved after the reinforcement with MgO and carbon nanotube (CNT), and also heat treatment of T6. The stress–strain curve of the composites is tested by a material testing machine. The maximum tensile and compression strengths are obtained at Al2024-0.2 wt.% (MgO 50% + CNT 50%) the composite as 226 MPa and 684 MPa, respectively .The hardness, compression, and tensile strengths of the hybrid composites are higher than 1.51, 1.39, and 1.31 than that of the base metal. After heat treatment of T6, the maximum harness, compression, and tensile strengths are obtained by 102 HB, 730 MPa, and 277 MPa, respectively, which are 1.82, 1.49, and 1.61 times higher hardness than that that of the base Al2024 alloy. The main strengthening mechanism of nano-MgO particles and MWCNTs-reinforced Al2024/MgO/CNTs composites is observed by the precipitation strengthening mechanism.

In this work, the Al– x Mg–MgO composites were fabricated via stir casting method. The different amounts of Mg (1, 3 and 5 wt%) and MgO (0.5, 1.0 and 1.5 wt%) were added to the aluminum matrix, and the composites were casted at various temperatures of 700, 800 and 900 °C. The effects of the casting temperature (°) and the Mg (wt%) and MgO (wt%) ratios on the microstructure, physical and mechanical properties of the composites were investigated. The scanning electron microscope with electron-dispersive spectrum, density (g/cm 3 ), porosity (%), hardness (HR-15T) and compression (MPa) test analyses were conducted on the composites. The results were also analyzed with the Taguchi experiment design method with ANOVA. The properties of the composites changed depending on the process parameters and ratios of Mg element and MgO particles. The minimum density and porosity contents were obtained as 2.62 g/cm 3 and 0.6%, respectively. The increase in the casting temperature contributed to the wettability and so the properties of the samples to some extent. The additions of Mg and MgO improved the hardness (72.8 HR-15T) and compression strength (646.4 MPa) of the composites. It can be said that the main strengthening mechanisms of the Al– x Mg– x MgO composites for this study were the solid solution and dispersion strengthening mechanisms.

The aim of the study is to research and compare the influences of the confirmed cases, test number and time range on the death and recovery rates in the United State of America, China, and Turkey, and to find out the effect of the epidemic in the near future of Turkey. The modelling and prediction of effects of the day, case and test numbers of COVID-19 infection in the USA, China and Turkey are carried out using the artificial neural network approach (ANN). The system are trained and tested with the different numbers of neurons, hidden layers and activation functions to increase the reliability and accuracy of model. The proposed models have a high R2 value for China and Turkey. We can say according to the results that the measures taken by the USA are inadequate. The formulation is applied to predict the effect of Covid-19 infection in Turkey. The test number that is an important factor in detecting the cases should be increased. The results show a good fit between the observed data and those obtained by the ANN model. If the precautions are strictly followed, the case number will be decreased significantly after 160 days for Turkey according to result of the proposed model but due to the uncontrolled variables, this time may result in between 200 and 250 days.

The growing attention regarding aluminum alloy matrix composites within the aerospace, automotive, defense, and transportation industries make the development of new engineering materials with the improved mechanical properties. Currently, materials are selected because of their abilities to satisfy engineering demands high for strength-to-weight ratio, tensile strength, corrosion resistance, and workability. These properties make aluminum alloys and aluminum matrix composites (AMCs) an excellent option for various industrial applications. Soft computing methods such as the artificial neural network (ANN), adaptive-neuro fuzzy inference systems (ANFIS), and Taguchi with ANOVA are the most important approaches to solve the details of the mechanism and structure of materials. The optimal selection of variables has important effects on the final properties of the alloys and composites. The chapter presents original research papers from our works and taken from literature studies dealing with the theory of ANN, ANFIS, and Taguchi, and their applications in engineering design and manufacturing of aluminum alloys and AMCs. Also, the chapter identifies the strengths and limitations of the techniques. The ANFIS and ANN approaches stand out with wide properties, optimization, and prediction, and to solving the complex problems while the Taguchi experimental design technique provides the optimum results with fewer experiments.

Metal matris kompozitler havacılık, savunma sanayii, otomobiller ve diğer önemli yapısal uygulamalar gibi çeşitli alanlarda yaygın olarak kullanılmaktadır. Alüminyum ve alaşımları hafifliği yanı sıra sağlamlığı ve kolay şekillendirilebilme özellikleri sayesinde endüstride giderek artan kullanım alanına sahip olmuştur. Alüminyum matrisli kompozitlerde takviye elamanı olarak Al2O3, SiC, TiC, MgO, CNT ve B4C yaygın olarak kullanılır. Bu alışmada, Al-bazlı metal matris kompozitlerin mekanik özelliklerini incelemek için matematiksel ve sonlu eleman modellemesi kullanılmıştır. Basınç, sinterleme sıcaklığı ve sinterleme süresine bağlı kalarak porozite içeriği uyarlanabilir nöro-bulanık çıkarım sistemi (ANFIS) yöntemi kullanılarak relatif yoğunluklar ise yapay sinir ağları (ANN) yöntemi ile başarılı bir şekilde analiz edilmiştir. Toz metalürjisi yöntemiyle üretilen ve SiC ile güçlendirilmiş alüminyum-magnezyum matrisli kompozitlerin porozite içeriği ANFIS yöntemi kullanılarak incelenmiştir. ANFIS yaklaşımında, dört giriş parametresi, ağırlıkça %SiC oranını, kullanılan basıncı (MPa), sinterleme sıcaklığını (⁰C), sinterleme zamanını (dk) ve bir çıkış parametresi porozite (%) oranını kullanılmıştır. Analizlerin korelasyon katsayılarının ve istatiksel hata oranlarının iyi olduğu görülmüştür. Toz metalürjisi yöntemiyle üretilen Al-Mg-Al2O3 kompozitlerin relatif yoğunluk değerleri ANN yöntemiyle incelenmiştir. Sistemin tahmin oranın %81olduğu ve kabul edilebilir sınırlar içerisinde olduğu söylenebilir. Ayrıca, Taguchi yaklaşımı ile her iki güçlendirici içeren kompozitlerin relatif yoğunluklar analiz edilmiştir ve sonuçlar karşılaştırılmıştır.

ASTM A356 (ISO AlSi7Mg) aluminum alloys are widely used in automotive and aircraft industries but they are selected mainly as automobiles wheel rim materials. They are composed of magnesium and silicon elements for improving corrosion and strength properties. Wheel rim materials are often electroplated by rim paints for decorative views and durability considerations. In this study; aluminum A356 alloy was coated by hard anodic oxidation method. 14 samples are prepared from an automobiles original 14 inch A356 aluminum alloy wheel rim. Samples are machined by 4x20x20 mm in dimensions for hard anodic oxidation. Three different case depths of hard anodic oxidation about 45, 65 and 90μm are applied on samples. Micro-structural investigations, micro-hardness surveys and the case depths of samples are thoroughly studied. The applicability of hard anodic oxidation method on wheel rim material A356 alloy is examined. The micro-structural surveys and micro-hardness tests proved that A356 aluminum alloy samples were hard anodic oxidized up to 90μm in coating thickness.

Kompozit malzemelerin geleneksel malzemelerle karsilastirildiginda dayanima bagli olarak yogunluk ve elastisite modulu ozelliklerinin yuksek olmasi bu malzemelere talebi arttirmistir. Ek olarak bu malzemelerin daha yuksek dayanim ve rijitlige sahip olmasi, makine elamaninin agirliginin azalmasi anlamina gelmektedir. AL 2024 matrisli kompozit malzemelerin uretiminde kokil kaliba dokum yontemi kullanilmis olup deneylerdeki asinma agirlik kaybi olarak ele alinmistir. Bu calismada agirlikca %50 MgO ve %50 MWCNT karistirilmis ve %0,2 - %0,5 - %1 - %2 oranlarinda matris malzemesine ilave edilmistir. MgO/MWCNT katkili Al 2024 kompozitlerin sertlik ve asinma davranisi Rockwell sertlik testiyle ball-on-disk asinma test cihazi kullanilarak incelenmistir. Elde edilen degerler karsilastirilarak kompozit malzemelerin asinma ozellikleri uzerindeki etkileri ortaya konulmustur. 5N yuk etkisi altinda 250 m mesafede asinma deneyine tabi tutulan kompozit malzemenin agirlik kaybi goz onunde bulundurularak yuzde asinma miktarlari incelenmistir. Guclendirici ilavasi ile kompozitlerin sertlik degerleri dogrusal olarak arttigi ve asinma yuzdesi de ayni sekilde azaldigi gozlemlenmistir. Guclendirici ilavesi icin en iyi oran agirlikca % 1 (50% MgO +50% CNT) karisimidir.

The multi-walled carbon nanotubes (MWCNTs) have drawn great attention due to their exceptional mechanical, physical, thermal and electrical properties. The MWCNTs as the reinforcements significantly improved the properties of materials. However, the major challenges in composites containing CNTs are the poor wettability and poor interfacial bonding between matrix and CNTs. In this study, the used MWCNTs have a diameter of 8–10 nm and 1.5 μm in length. MWCNTs are purified in HNO3: H2SO4, sensitized in Sn solution and activated in Pd solution at 90 °C, and coated with the Nickel and Cobalt elements using an electroless coating method. The holding time in the bath is 15, 30 and 60 min, and the bath concentration is also changed. The coatings are characterized by Scanning Electron Microscopy (SEM) equipped with electron dispersive spectrum (EDS), elemental mapping, x-ray diffraction (XRD), Raman spectroscopy, Transmission Electron Microscopy (TEM) and Fourier Transform Infrared (FTIR) spectrometer. The results showed that the Ni and Co coating layers are successfully formed on the surface of MWCNTs. The deposition rate is affected by the holding time and the bath concentration. The optimal results are obtained at the holding time of 60 min in the C concentration sample.

Toz metalurjisi yöntemi, alüminyum alaşımı esaslı metal matris kompozitlerinin üretimi için diğer geleneksel yöntemlere göre umut vadeden alternatif bir yöntemdir.Bu çalışmada, toz metalurjisi yöntemi ile hazırlanan SiC içeren alüminyum alaşım esaslı metal matris kompozitlerin işlem parametrelerinin Taguchi ve Varyans Analizi (ANOVA) yaklaşımı ile görünür yoğunluk üzerine etkisi araştırılmıştır.Taguchi'nin L16 dikey dizisi, minimum görünür yoğunluk elde etmek amacıyla işlem parametrelerini optimize etmek için kullanılmıştır.Dikkate alınan parametreler; ağırlıkça SiC oranı (%15 ve 30), sıkıştırma basıncı (260 ve 520 MPa), sinterleme sıcaklığı (300 ve 500°C) ve sinterleme zamanı (30 ve 90 dk.) ve bununla birlikte çıkış parametresi de görünür yoğunluktur.ANOVA, her bir parametrenin çıkış parametresi üzerindeki etkisini

Bu calismada, magnezyum oksit (MgO)ilave edilmis aluminyum (Al) - MgO kompozitler toz metalurjisi yontemiyle uretilmistir. Kompozitlerde MgO guclendirici olarak agirlikca %10 oraninda ilave edilmis olup guclendiricinin ortalama capi <40 nm boyutundadir. Kompozitler, karistirma, sikistirma ve 5 saat sinterleme suresi ile farkli sinterleme sicakliklarina (500 oC – 550 oC – 600 oC) tabi tutulmuslardir. Kompozitlerin mikroyapilari optik mikroskop ve taramali elektron mikroskobu (SEM) araciligiyla incelenmistir. Kompozitlerin teorik yogunluklari karisim kanununa gore ve olculen yogunluklari Arsimed prensibine gore arastirilmistir. Teorik yogunluk degerleri ve olculen yogunluk degerleri kullanilarak urunlerin porozite icerigi belirlenmistir. Ayrica kompozitlere sertlik testi uygulanarak mekanik ozellikleri arastirilmistir. MgO nano partikul aluminyum matrsinin sertligini onemli derecede arttirmistir. Maksimum sertlik degeri Al-10 MgO kompozitte 104 HB olarak elde edilmistir. Tane buyumesi sertlikte liner buyumeyi engelledigi gorulmustur. Artan sicaklikla kompozitlerde tane buyumesi meydana gelmekte, porozite icerigi azalmakta ve sertlikte farkli degerler elde edilmektedir. Maksimum relatif yogunluk 600 oC sintermele sicakligi ile elde edilmistir.

Wear of metals is one of the most important mechanisms encountered on engineering basis. Especially in places where there is friction, it is important to use engineering materials with high friction resistance. In this study, 40 nm diameter nano magnesium oxide and 1.5 micron long and 9.5 nm diameter multiple walled carbon nano tubes were added to Al-Cu-Mg alloy. 50 wt% MGO and 50 wt% MWCNT were mixed and added to the matrix material in 1wt% and the composite materials were produced by the semi-solid mixing method. The aim of this study was to investigate the major tribological factors affecting the abrasive wear behavior of Al-Cu-Mg composites reinforced with MGO/MWCNT. Composite materials were produced by semi-solid mixing method. The wear behavior of MGO/MWCNT reinforced Al-Cu-Mg alloy aluminum matrix composites (Al MMCs) was investigated. Wear properties were investigated under different loads and the shear rate and shear distance were kept constant. Abrasion tests were carried out considering the weight loss at 500 m distance under 2N and 5N load on the ball-on-disc type wear device. Al-Cu-Mg wear weight loss was reduced by approximately 49% with the addition of 50% CNT 50% MgO 1% wt.

In the present study, AA2124/25%vol.SiCp-T4 aluminum metal matrix composite plates were successfully friction stir butt joined using various welding parameters. The influence of the welding parameters on the distribution, micro-hardness and tensile strength of the joints was investigated and the joint efficiency was determined. The temperature measurements were obtained from four points at the each side of the weld, namely tool advancing and tool retreating side, from the 15 mm away from the weld center. Based on these measurements, the average peak temperature in the weld nugget was predicted according to studies in literature. As a result of the study, the temperature dissipation show that the max. 180-270 °C occurred at 15 mm away from the centerline of the weld. The maximum and minimum values of joint performance was obtained at 1400/40 and 1400/100 welding parameters as 73% and 59.32%, respectively. It was not detected a noticeable differences in micro-hardness measurements of the stir zone. It is determined that micro-hardness distribution in stir zone is in accordance with literature supported results due to dynamic recrystallization.