Farklı Oranlarda Ca Katkısının Döküm ZK60 Mg Alaşımlarının Mikroyapı ve Mekanik Özellikler Üzerindeki Etkisinin İncelenmesi

Year 2023, Volume: 26 Issue: 3, 1061 - 1069, 01.10.2023

Aykan Akbaş , Muzaffer Zeren

https://doi.org/10.2339/politeknik.1052154

Cited By: 3

Abstract

Ağırlıkça farklı Ca (%) oranlarında katılarak elde edilen olarak bilinen döküm Mg-6Zn-0.5Zr (ağ. %) ZK60 Mg alaşımının 345°C’de sıcak çekme testleriyle mikroyapı ve mekanik özellikleri incelenmiştir. Deneysel bu çalışmada, alaşım düşük basınçlı kokil döküm (LPDC) yöntemiyle üretilmiştir. Döküm alaşımının mikroyapı karakterizasyonunda ağ.% 0.8Ca oranına kadar tane boyutu küçülmüş, Ca oranı yavaş yavaş arttırıldıkça tane boyutu da 345°C sıcaklıkta yaklaşık ~60 µm boyutuna ulaştığı gözlemlenmiştir. Sonuç olarak, ağ.% 0.4Ca oranına bağlı olarak tane sınırlarında şerit benzeri Mg-Zn intermetalik yapıyı tane köşelerinde ise kabalaşmış üçlü Ca-Mg-Zn intermetalik yapısını oluştururlar. ağ.% 1.6Ca ilavesinde akma ve çekme mukavemetleri mukayese edilebilecek şekilde 345°C sıcaklıkta sırasıyla 37.6 Mpa ve 39.7 MPa değerlerine düştüğü görülmüştür. Kopma uzaması ise, bunların tam tersine sıcaklığa bağlı tekstür yumuşaması neticesi mekanik özelliklerdeki artışına bağlı olarak, ağ.% 1.6Ca oranında 1.26 % olarak ölçülmüştür. Aşınma oranı ağ.% Ca oranından etkilenmiştir ağ.% 1.2Ca oranında aşınma hızı 3.70 x10-3 mm3/m olarak ölçülmüştür. Benzer şekilde ZK60 Magnezyum alaşımı sertlik değerlerinde de Ca içeriğine bağlı artışlar grafiklerde gösterilmiştir. Bu çalışmada döküm ZK60 magnezyum alaşımlarına % ağ. Ca katkısıyla sıcaklığa bağlı etkisinin mekanik özellikleri geliştirdiği gözlemlenmiştir.

Keywords

ZK60 Alaşımı, Ca ilavesi, Mikroyapı, Sıcak Çekme Testi, Mekanik Özellikler

Supporting Institution

Kocaeli Üniversitesi Bilimsel Araştırma Projeleri (BAP) Koordinasyon Birimi

Project Number

2018/047

Thanks

Yazarlar Kocaeli Üniversitesi Bilimsel Araştırma Projeleri (BAP) Koordinasyon Birimi'ne bu projeye sağlamış oldukları finansal hakkı nedeniyle teşekkürlerini sunar.

Investigation of the Effect of Various Ca Content on Microstructure and Mechanical Properties of As-cast ZK60 Magnesium Alloys

Abstract

The effect of various Ca content on microstructure and mechanical properties of as-cast Mg-6Zn-0.5Zr (wt.%) Mg alloys with hot tensile testing at 345°C were investigated. The alloy was produced with the LPDC method [1]. Microstructural characterization as-cast alloy demonstrated that wt.% Ca content increase, grain size decreases till wt.% 0.8Ca, the further increase affects gradual change in grain size to ~60 µm at 345°C. Therefore, increase in Ca ratio from 0.4 wt% forming to strip-like Mg-Zn intermetallics at grain boundaries, Ca-Mg-Zn ternary phase at grain boundary corners. Dramatical decrease in yield and tensile strength at wt% 1.6Ca addition is 37.6 MPa and 39.7 MPa respectively which is relatively low at 345°C due to the absence of retarded DRX’ed small particles prohibited the grain growth after the TMT process. Conversely, elongation-to-fracture increases were observed as 1.26 at 345°C showing the temperature-dependent texture softening results in improvement of mechanical properties. Wear rate is also affected from wt.% Ca addition so the gradual increase up to 1.2 wt% Ca is 3.70 x 10-3 mm3/m. Similarly, a gradual increase in hardness values was obtained with Ca addition in ZK60 alloy. In this study, the effect of temperature-dependent Ca addition (wt %) on gradual enhancement in mechanical properties was observed at as-cast magnesium alloys.

Keywords

ZK60 Alloy, Ca addition, Microstructure, Hot Tensile Testing, Mechanical Properties

Project Number

2018/047

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