Titanyum ile tane inceltmenin Al-25Zn alaşımının mikroyapı, mekanik ve korozyon özelliklerine etkisinin incelenmesi

Öz

Bu çalışmada, bir adet ikili Al-25Zn alaşımı ve Al-25Zn-0,01Ti, Al-25Zn-0,03Ti, Al-25Zn-0,04Ti, Al-25Zn-0,05Ti, Al-25Zn-0,075Ti, Al-25Zn-0,1Ti, Al-25Zn-0,2Ti, Al-25Zn-0,4Ti, Al-25Zn-0,6Ti, Al-25Zn-0,8 ve Al-25Zn-1Ti olmak üzere 11 adet üçlü alüminyum-çinko-titanyum alaşımı kokil kalıba döküm yöntemiyle üretildi. Üretilen alaşımların içyapı, mekanik ve korozyon özellikleri incelendi. İçyapı incelemeleri elektron mikroskobu(SEM) ve X-ışını kırınım(XRD) çalışmalarıyla gerçekleştirildi. Mekanik özellikler ise Brinell sertlik ölçüm yöntemi ve çekme deneyi yardımıyla belirlendi. Korozyon deneyleri elektrokimyasal test düzeneğinde ASTM G5 standardına uygun olarak gerçekleştirildi. Al-25Zn ve Al-25Zn-Ti alaşımlarının içyapılarının ana matris olarak α ve η fazlarından oluştuğu, titanyum oranının %0,01’i aşması durumunda içyapıda Al₃Ti fazının çökelmeye başladığı gözlendi. Ayrıca Al-25Zn-Ti alaşımlarındaki dendrit veya tanelerin boyutunun ikili alaşıma göre çok daha küçük olduğu görüldü. Al-25Zn alaşımına %0,01 oranında yapılan titanyum katkısının sertlik, akma ve çekme mukavemeti değerlerini artırdığı bu orandan daha yüksek katkıların ise azalttığı gözlendi. Titanyum katkılarının korozyon özelliklerini olumsuz etkilediği görüldü. Farklı oranlardaki titanyum katkıları nedeniyle Al-25Zn alaşımının mekanik ve korozyon özelliklerinde meydana gelen değişimler alaşımların yapısal özelliklerine dayandırılarak açıklandı.

 

Anahtar Kelimeler

• Al-25Zn-Ti alaşımları,Titanyum katkısı,Tane inceltme,Mekanik özellikler,Korozyon

Effect of grain refinement with titanium on the microstructure, mechanical and corrosion properties of Al-25Zn alloy

Öz

In this study, one binary Al-25n alloys and eleven ternary aluminum-zinc-titanium alloys, Al-25Zn-0.01Ti, Al-25Zn-0.03Ti, Al-25Zn-0.04Ti, Al-25Zn-0.05Ti, Al-25Zn-0.075Ti, Al-25Zn-0.1Ti, Al-25Zn-0.2Ti, Al-25Zn-0.4Ti, Al-25Zn-0.6Ti, Al-25Zn-0.8 and Al-25Zn-1Ti, were produced by permanent mold casting method. Structural, mechanical, and corrosion properties of the tested alloys were investigated. Structural investigations were carried out with scanning electron microscope (SEM) and X-ray diffraction (XRD) studies. Mechanical properties of the alloys were determined with the Brinell hardness and tensile tests. Corrosion tests were carried out with electrochemical test setup in accordance with ASTM G5 standard. Al-25Zn and Al-25Zn-Ti alloys were composed of α and η phases as the main matrix, and it was observed that Al₃Ti phase began to precipitate in the microstructure when the titanium content exceeded 0.01%. In addition, the size of dendrites or grains of the Al-25Zn-Ti alloys was found to be much smaller than that of binary alloy. The hardness, yield strength, and tensile strength values of the Al-25Zn alloy significantly increased with the 0.01%Ti addition, but when Ti content exceeded 0.01%, these values decreased with increasing titanium content. It was observed that titanium addition had a negative effect on the corrosion properties of the Al-25Zn alloy. The change on the mechanical and corrosion properties of the Al-25Zn alloy due to the titanium addition in different ratios have been explained based on the structural properties of the alloys.

 

Anahtar Kelimeler

• Al-25Zn-Ti alloys,Titanium additive,Grain refinement,Mechanical properties,Corrosion

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