Seryum katkılanan ZE41 Mg-Ce alaşımlarının üretilmesi, korozyon ve mekanik özelliklerinin belirlenmesi
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Tarih
2015
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Hatay Mustafa Kemal Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
ZE41 magnezyum alaşımları; zayıf korozyon direncine sahip olsalar da mükemmel mekanik özellikleri nedeniyle askeri, uzay, savunma sanayii ve otomotiv sektöründe kullanılmaktadır. Bu çalışmada korozyon ve mekanik özelliklerine etkisini inceleme amacıyla ZE41 alaşımı ve ağırlıkça %0.3, %0.6 ve %0.9 oranında seryum (Ce) katkılı ZE41Ce1, ZE41Ce2, ZE41Ce3 mekanik alaşımlama (MA) yöntemi ile üretildi. Alaşımlar, katkı oranlarına bağlı olarak mikro/nano sertlik ve korozyon deneyleri için uygun boyutlarda preslendi. Bu alaşımların hazırlanmasından sonra, taramalı elektron mikroskobu (SEM), X-ışını kırınımı yöntemi (XRD), mikro ve nanoçentik testsleri alaşımların mekanik özelliklerini incelemek için kullanıldı. Mikrosertlik testi yük aralığı 0.245 ile 9.8 N arasında değişen yük aralığında Vickers ve Knoop uçları kullanılarak yapıldı. Hem Vickers hemde Knoop uçları için, alaşımların sertlikleri belirgin şekilde yüke bağımlılık gösterdi (ters çentik boyutu etkisi (TÇBE), ve çentik boyutu etkisi (ÇBE)). Mikrosertlik deneyi sonuçları Meyer Kanunu, Orantılı Numune Direnci Modeli, Düzeltilmiş Orantılı Numune Direnci Modeli, Hays-Kendall modeller kullanılarak analiz edildi. Bu çalışmada, yükten bağımsız sertliğin hesaplamasında en iyi modelin Hays-Kendall Modeli olarak bulundu. Statik sertlik deneylerinden ZE41, ZE41Ce1, ZE41Ce2 ve ZE41Ce3 alaşımlarına ait elastik modül değerleri sırasıyla 84.832, 49.178, 45.735 ve 44.096 GPa'dır. Sonuç olarak; Seryum katkısının artmasıyla elastik modül değerlerinin azaldığı gözlendi. Bu alaşımların nanosertlik deneyleri 1000 ile 10000 μN artan yük aralığında ölçüldü. Nanosertlik testleri Triboindenter (Hysitron TI-950) cihazı ile Berkovich uç kullanılarak gerçekleştirildi. Yük-yerdeğiştirme eğrilerinin analizi literatürde en yaygın olarak kullanılan Oliver-Pharr Metodu ile yapıldı. Mikrosertlik testlerine benzer şekilde, Nanosertlik deney sonuçları da, Meyer Kanunu, Orantılı Numune Direnci Modeli, Düzeltilmiş Orantılı Numune Direnci Modeli, Hays-Kendall. modelleri kullanılarak analiz edildi. Sonuç olarak, bu çalışmada nanosertlik değerleri sırasıyla ZE41, ZE41Ce1, ZE41Ce2 ve ZE41Ce3 için 0.906, 0.840, 0.802, 1,546 GPa olarak elde edildi. Nanosertlik deneylerinden ZE41, ZE41Ce1, ZE41Ce2 ve ZE41Ce3 alaşımlarına ait elastik modül değerleri sırasıyla 51.192, 47.736, 39.541 ve 36.286 GPa'dır. Sonuç olarak, mikrosertlik sonuçlarına benzer olarak, seryum katkısının artmasıyla elastik modül değerlerinin azaldığı gözlendi. Polarizasyon testleri % 3,5'lik NaCl çözeltisinde yapıldı. Polarizasyon tarama hızı 1 mVs-1 olarak seçildi ve potansiyel aralığı -500 ile +250 mV aralığında belirlendi. ZE41, ZE41Ce1, ZE41Ce2 ve ZE41Ce3 alaşımları için korozyon potansiyeli, korozyon akımı ve lineer polarizasyon direnci Tafel Metodu ile belirlendi. Artan seryum oranı ile korozyon akımının azalarak korozyon direncinin arttığı gözlendi.
Magnesium alloy ZE41, used extensively in the military, aerospace, defence, and car industry, because of their excellent mechanical properties albeit poor corrosion resistance. In this study, ZE41 and alloys having different Cerium amount (mass %0.3, %0.6 and %0.9 Ce) to investigate the corrosion and mechanical properties that produced by Mechanical Alloying (MA) method under argon atmosphere. The alloys were pressed in appropriate dimension for micro/nano and corrosion experiments. After preparation of these alloys, scanning electron microscopy (SEM), X-ray diffraction method (XRD), micro and nanohardness test were used to examine the mechanical properties of the alloys. Microhardness test were carried out using Vickers and Knoop indenter that the loads ranging 0.245 to 9.8N. Both Vickers and Knoop indenters were used, hardness of the alloys exhibit significant load-dependence (i.e reverse indentation size effect, (RISE), and indentation size effect, (ISE)). The experimental microhardness results were analyzed by Meyer's law, Proportional Specimen Resistance model, Modified Proportional Specimen Resistance Model, and Hays-Kendall model. The best model for the load-independent microhardness calculation is our case was found to be Hays-Kendall Model. The elastic modulus values obtained from static hardness experiments of ZE41, ZE41Ce1, ZE41Ce2 and ZE41Ce3 alloys were found 84.832, 49.178, 45.735 ve 44.096 GPa respectively. Consequently, the values of elastic modulus decreases with increasing cerium contribution. The nanohardness of these alloys were measured in the peak load range from 1000 to 10000 μN. The nanoindentation test were conducted with a Berkovich indenter using a fully calibrated Triboindenter (Hysitron TI-950) equipment. The most common Oliver-Pharr Method used the analysis of load-displacement curves. Same as the microhardness, nanohardness results were analyzed by Meyer's law, Proportional Specimen Resistance Model, Modified Proportional Specimen Resistance Model, Hays-Kendall model. As a results, in the present study the corresponding naohardness values were 0.906, 0.840, 0.802, 1.546 GPa for ZE41, ZE41Ce1, ZE41Ce2 and ZE41Ce3, respectively. The elastic modulus values obtained from nanohardness experiments of ZE41, ZE41Ce1, ZE41Ce2 and ZE41Ce3 magnesium alloys were found 51.192, 47.736, 39.541 and 36.286 GPa respectively. Consequently, same as the microhardness results, the elastic modulus values decreases with increasing cerium contribution. The polarization tests were carried out at NaCl solution (mass % 0.09). The potential scan rate chosen was 1 mVs-1 and the potential range were identified from -500 to +250 mV. Corrosion potential, corrosion current and linear polarization resistance of ZE41, ZE41Ce1, ZE41Ce2 and ZE41Ce3 were determined by the Tafel Method. The results showed that corrosion resistance increases and corrosion current decreases with increasing Ce ratio.
Magnesium alloy ZE41, used extensively in the military, aerospace, defence, and car industry, because of their excellent mechanical properties albeit poor corrosion resistance. In this study, ZE41 and alloys having different Cerium amount (mass %0.3, %0.6 and %0.9 Ce) to investigate the corrosion and mechanical properties that produced by Mechanical Alloying (MA) method under argon atmosphere. The alloys were pressed in appropriate dimension for micro/nano and corrosion experiments. After preparation of these alloys, scanning electron microscopy (SEM), X-ray diffraction method (XRD), micro and nanohardness test were used to examine the mechanical properties of the alloys. Microhardness test were carried out using Vickers and Knoop indenter that the loads ranging 0.245 to 9.8N. Both Vickers and Knoop indenters were used, hardness of the alloys exhibit significant load-dependence (i.e reverse indentation size effect, (RISE), and indentation size effect, (ISE)). The experimental microhardness results were analyzed by Meyer's law, Proportional Specimen Resistance model, Modified Proportional Specimen Resistance Model, and Hays-Kendall model. The best model for the load-independent microhardness calculation is our case was found to be Hays-Kendall Model. The elastic modulus values obtained from static hardness experiments of ZE41, ZE41Ce1, ZE41Ce2 and ZE41Ce3 alloys were found 84.832, 49.178, 45.735 ve 44.096 GPa respectively. Consequently, the values of elastic modulus decreases with increasing cerium contribution. The nanohardness of these alloys were measured in the peak load range from 1000 to 10000 μN. The nanoindentation test were conducted with a Berkovich indenter using a fully calibrated Triboindenter (Hysitron TI-950) equipment. The most common Oliver-Pharr Method used the analysis of load-displacement curves. Same as the microhardness, nanohardness results were analyzed by Meyer's law, Proportional Specimen Resistance Model, Modified Proportional Specimen Resistance Model, Hays-Kendall model. As a results, in the present study the corresponding naohardness values were 0.906, 0.840, 0.802, 1.546 GPa for ZE41, ZE41Ce1, ZE41Ce2 and ZE41Ce3, respectively. The elastic modulus values obtained from nanohardness experiments of ZE41, ZE41Ce1, ZE41Ce2 and ZE41Ce3 magnesium alloys were found 51.192, 47.736, 39.541 and 36.286 GPa respectively. Consequently, same as the microhardness results, the elastic modulus values decreases with increasing cerium contribution. The polarization tests were carried out at NaCl solution (mass % 0.09). The potential scan rate chosen was 1 mVs-1 and the potential range were identified from -500 to +250 mV. Corrosion potential, corrosion current and linear polarization resistance of ZE41, ZE41Ce1, ZE41Ce2 and ZE41Ce3 were determined by the Tafel Method. The results showed that corrosion resistance increases and corrosion current decreases with increasing Ce ratio.
Açıklama
Anahtar Kelimeler
Fizik ve Fizik Mühendisliği, Physics and Physics Engineering
