Mekanik Alaşımlama ile Üretilen B4c ve Cnt Partikül Takviyeli Al7xxx(Al-zn-mg) Matris Malzemesinin Mikroyapı, Mekanik ve Elektriksel Özelliklerinin İncelenmesi
Yükleniyor...
Dosyalar
Tarih
2023
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Selçuk Üniversitesi Fen Bilimleri Enstitüsü
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Son zamanlarda gelişen teknolojiye bağlı olarak, endüstriyel alanda kullanılan birçok malzemede
birden fazla özelliğin aynı anda bulunması ihtiyacı ortaya çıkmıştır. Bu kapsamda üretilmesi istenen yeni
nesil kompozit malzemelerin aynı zamanda daha hafif ve daha dayanıklı olması aranan özelliklerdendir.
Toz metalurjisi ve mekanik alaşımlama yöntemi kullanılarak üretilen yoğunluğu düşük, ucuz, hafif ve
üretimi kolay alüminyum esaslı kompozitler bu ihtiyacı karşılamaya aday malzemelerdir. Bu çalışmada
farklı üretim parametreleri (öğütme süresi, sinterleme) ve farklı takviye türleri (B4C, CNT) kullanılarak
AA7XXX(Al-Zn-Mg) serisi kompozit malzemeler mekanik alaşımlama yöntemi ile üretilmiştir. Bu
kapsamda ticari AA7XXX (katkısız), ağ. %5B4C katkılı, %5B4C / %1CNT katkılı ve %1CNT katkılı dört
farklı toz kompozisyonları oluşturulmuştur. Başlangıçta 42 µm boyutlarında olan metal tozları 0,5, 1, 2, 4
ve 8 saat öğütme işlemine tabi tutulmuş ve öğütme işlemi sonrası tozların presleme ve sinterleme işlemi
yapılmıştır. Tozların öğütme işlemi sonrası birleştirilmesi işlemi soğuk presleme-ısıtma ve sıcak presleme
olacak şekilde iki aşamada gerçekleştirilmiştir. Hazırlanan 4 farklı grup tozların partikül boyutu analizi,
toz morfolojisi için taramalı elektron mikroskop (SEM) görüntüleri ve X-ışını kırınımı (XRD) ile toz
karakterizasyonları yapılmıştır. Daha sonra ise sinterleme işlemi sonrası üretilen kompozit malzemelerin
XRD analizi, optik mikroskop (OM) görüntüleri ve SEM görüntüleri incelenmiş ve yoğunluk, sertlik,
eğilme dayanımları ve elektrik iletkenlik özellikleri incelenmiştir. Sonuç olarak mekanik öğütmenin
partikül boyutunu önemli bir seviyede düşürdüğü ve bu düşüşün mekanik özellikleri olumlu olarak
arttırdığı belirlenmiştir. Ayrıca ön pres olmadan yapılan sinterleme de daha az boşluklu bir yapı olduğu
tespit edilmiş ve yoğunluk değerlerinin 2,54 g/cm3
ile 2,74 g/cm3
aralığında olduğu belirlenmiştir. Sertlik
değerlerinde ise %5B4C / %1CNT katkılı hibrit malzemelerin soğuk pres sinterlemede %51, sıcak pres
sinterlemede ise %81 oranında iyileşme gözlemlenmiştir. XRD sonuçlarına göre başlangıçta 45 nm olan
kristalit boyutunun öğütme sonrası 23 nm’ye düştüğü ve kristalit boyutundaki azalmanın mekanik
özellikleri artırdığı tespit edilmiştir. Elektrik iletkenlik sonuçlarına göre ise CNT katkısının direnç
değerlerini %17 oranında azalttığı belirlenmiştir. 3 nokta eğme deneyi sonuçları, sırasıyla 1064, 1892 ve
2300 N eğme dayanımı ve kopma uzamaları sırasıyla 4.39, 2.63 ve 3 mm olarak ölçülmüştür. Sonuç
olarak; bu tez çalışmasında üretilen AA7XXX kompozisyonlarının mekanik dayanımı artarken elektrik
direncini koruduğu ayrıca üretilen malzemelerin aynı anda birden fazla özelliği barındırdığı ve
endüstriyel uygulamalar için önemli alternatif malzemeler olabileceği ortaya koyulmuştur.
Due to the recently developed technology, the need for more than one property to be present at the same time in many materials used in the industrial field has emerged. In this context, the new generation composite materials to be produced are also lighter and more durable. Aluminum based composites with low density, cheap, light weight and easy to produce produced by using powder metallurgy and mechanical alloying method are candidate materials to meet this need. In this study, AA7XXX(Al-Zn-Mg) series composite materials were produced by mechanical alloying method by using different production parameters (grinding time, sintering) and different types of reinforcement (B4C, CNT). In this context, commercial AA7XXX (unadulterated), network. Four different powder compositions with 5% B4C doped, 5% B4C/1% CNT doped and 1% CNT doped were created. The metal powders, which were initially 42 μm in size, were subjected to milling for 0.5, 1, 2, 4 and 8 hours and after the grinding process, the powders were pressed and sintered. The joining process of the powders after the milling process was carried out in two stages as cold pressing-heating and hot pressing. Particle size analysis of 4 different groups of powders, scanning electron microscope (SEM) images for dust morphology and dust characterizations were performed by X-ray diffraction (XRD). Then, XRD analysis, optical microscope (OM) images and SEM images of composite materials produced after the sintering process were examined and their properties such as density, hardness, flexural strength and electrical conductivity were examined. As a result, it was determined that mechanical grinding significantly reduced the particle size and this decrease positively increased the mechanical properties. In addition, sintering without pre-press was found to be a structure with fewer gaps and density values were determined to be in the range of 2.54 g/cm3 to 2.74 g/cm3. In terms of hardness values, 51% improvement was observed in cold press sintering and 81% improvement in hot press sintering of hybrid materials with 5% B4C / 1% CNT additive. According to the XRD results, it was determined that the crystallite size, which was initially 45 nm, decreased to 23 nm after milling and that the decrease in crystallite size increased the mechanical properties. According to the electrical conductivity results, it was determined that the CNT additive reduced the resistance values by 17%. The results of the 3-point bending test, 1064, 1892 and 2300 N/mm2 flexural strength and elongation at break were measured as 4.39, 2.63 and 3 mm, respectively. After all; In this thesis study, it was revealed that the AA7XXX compositions produced in this thesis maintain their electrical resistance while increasing their mechanical strength, and that the materials produced have more than one property at the same time and can be important alternative materials for industrial applications.
Due to the recently developed technology, the need for more than one property to be present at the same time in many materials used in the industrial field has emerged. In this context, the new generation composite materials to be produced are also lighter and more durable. Aluminum based composites with low density, cheap, light weight and easy to produce produced by using powder metallurgy and mechanical alloying method are candidate materials to meet this need. In this study, AA7XXX(Al-Zn-Mg) series composite materials were produced by mechanical alloying method by using different production parameters (grinding time, sintering) and different types of reinforcement (B4C, CNT). In this context, commercial AA7XXX (unadulterated), network. Four different powder compositions with 5% B4C doped, 5% B4C/1% CNT doped and 1% CNT doped were created. The metal powders, which were initially 42 μm in size, were subjected to milling for 0.5, 1, 2, 4 and 8 hours and after the grinding process, the powders were pressed and sintered. The joining process of the powders after the milling process was carried out in two stages as cold pressing-heating and hot pressing. Particle size analysis of 4 different groups of powders, scanning electron microscope (SEM) images for dust morphology and dust characterizations were performed by X-ray diffraction (XRD). Then, XRD analysis, optical microscope (OM) images and SEM images of composite materials produced after the sintering process were examined and their properties such as density, hardness, flexural strength and electrical conductivity were examined. As a result, it was determined that mechanical grinding significantly reduced the particle size and this decrease positively increased the mechanical properties. In addition, sintering without pre-press was found to be a structure with fewer gaps and density values were determined to be in the range of 2.54 g/cm3 to 2.74 g/cm3. In terms of hardness values, 51% improvement was observed in cold press sintering and 81% improvement in hot press sintering of hybrid materials with 5% B4C / 1% CNT additive. According to the XRD results, it was determined that the crystallite size, which was initially 45 nm, decreased to 23 nm after milling and that the decrease in crystallite size increased the mechanical properties. According to the electrical conductivity results, it was determined that the CNT additive reduced the resistance values by 17%. The results of the 3-point bending test, 1064, 1892 and 2300 N/mm2 flexural strength and elongation at break were measured as 4.39, 2.63 and 3 mm, respectively. After all; In this thesis study, it was revealed that the AA7XXX compositions produced in this thesis maintain their electrical resistance while increasing their mechanical strength, and that the materials produced have more than one property at the same time and can be important alternative materials for industrial applications.
Açıklama
Anahtar Kelimeler
Bor Karbür, Karbon Nanotüp, Kompozit Malzemeler, Mekanik Alaşımlama, Mekanik Özellikler, Boron Carbide, Carbon Nanotube, Composite Materials, Mechanical Alloying, Mechanical Properties
Kaynak
WoS Q Değeri
Scopus Q Değeri
Cilt
Sayı
Künye
Doğan, K., (2023). Mekanik Alaşımlama ile Üretilen B4c Ve Cnt Partikül Takviyeli Al7xxx(Al-zn-mg) Matris Malzemesinin Mikroyapı, Mekanik ve Elektriksel Özelliklerinin İncelenmesi. (Doktora Tezi). Selçuk Üniversitesi, Fen Bilimleri Enstitüsü, Konya.
