Al50Si25B25 alaşımının mikroyapı, termal ve mekanik özelliklerinin incelenmesi

Bu çalışmada Al50Si25B25 alaşımı ark ergitme yöntemi ile külçe olarak üretilmiştir. Al50Si25B25 alaşımının faz analizi X-ışını difraksiyonu (XRD), morfolojik özellikleri taramalı elektron mikroskobu (SEM) ile termal özellikleri ise diferansiyel termal analiz (DTA) ve diferansiyel taramalı kalorimetre (DSC) ile araştırılmıştır. Alaşımın mekanik özelliği Vickers mikrosertlik (HV) testi ile incelenmiştir. XRD analizinden, Bor (B) ve Silisyum (Si) atomlarının Al kafesi içerisinde çözünerek α-Al(B,Si) katı çözeltisini oluşturduğu tespit edilmiştir. XRD ve SEM sonuçları, alaşımın mikro yapısının, α-Al(B,Si) katı çözeltisi, AlB2 intermetalik fazı ve Si fazlarından oluştuğunu göstermiştir. SEM sonuçları alaşımların morfolojik yapısının dendritik ve ötektik yapılar şeklinde oluştuğunu göstermiştir. DSC ve DTA sonuçları, α-Al(B,Si) fazının ergimesini ifade eden bir endotermik pik göstermiştir. Alaşımın mikro sertlik değeri oda sıcaklığında 108±15 HV olarak ölçülmüştür. Bu değer termal işlem sonucu artmış ve 300 ºC’de 232±9 HV değerine çıkmıştır. 300 ºC’den daha yüksek sıcaklıklarda alaşımın mikrosertlik değerinin azaldığı gözlenmiştir.

Anahtar Kelimeler:

Alaşım, Mikrosertlik, Mikroyapı, Katılaştırma, AlSiB alloy, Micro-Hardness, Microstructure, Arc melting

Investigation of microstructural, thermal and mechanical properties of Al50Si25B25 alloy

In this study, Al50Si25B25 alloy was produced as ingot by arc melting method. The microstructure of the Al50Si25B25 alloy was investigated by X-ray diffraction (XRD), the morphological properties were investigated by scanning electron microscopy (SEM), and its thermal properties were investigated by differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The mechanical properties of the alloy were investigated by Vickers microhardness (HV) test.The XRD result showed that B and Si atoms dissolved in the Al lattice to form the intermetallic phase of the α-Al (B, Si) solid solution. XRD and SEM results showed that the microstructure of the alloys consisted of α-Al(B,Si) solid solution, Si and AlB2 intermetallic phases. SEM results showed that the morphological structure of the alloys formed as dendritic and eutectic structures. DSC and DTA results showed an endothermic peak indicating the melting of the α-Al(B,Si) phase. The microhardness value of the alloy was measured as 108±15 HV at room temperature. This value increased as a result of the heat treatment and increased to 232±9 HV at 300 ºC. It was observed that the microhardness value of the alloy decreased at temperatures higher than 300 ºC.

Keywords:

AlSiB alloy, Micro-Hardness, Microstructure, Arc melting,

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