AlSiCu (LM24) Alüminyum Alaşımında Modifikasyon ve Tane İnceltmenin Mikroyapı ve Mekanik Özelliklere Etkisi

Bu çalışmada, AlSiCu alaşımına Stronyum (Sr) ile modifikasyon ve Al5TiB ile tane inceltme işlemi uygulanmıştır. Çalışmada AlSiCu alaşımı yaklaşık 150-200 ppm Sr ile modifikasyon ve %0,75 ve 1,5 Al5TiB ile tane inceltme işlemi uygulandıktan sonra metal ve kum kalıba döküm metodu ile üretilmiştir. Mikroyapı incelemeleri optik mikroskop (OM), tarama elektron mikroskobu (SEM/EDS analizi), mekanik özelikler; çekme testi ve sertlik ölçümleri ile değerlendirildi. Sonuç olarak; optik mikroskop (OM) incelemelerinde metal kalıba dökülen AlSiCu alaşımında Al-Si ötektiğinin daha homojen ve ince dağıldığı belirlendi. Sr modifikasyonu ile Al-Si ötektiğinin morfolojisinin değiştirdiği görülmüştür. Al5TiB ilavesi ile yapının özellikle metal kalıba dökülen alaşımda dendritlerin daha düzenli olduğu fakat boşluk miktarının arttığı görülmektedir. Tarama elektron mikroskobu (SEM) görüntülerinde kum kalıba ve metal kalıba dökülen Al5TiB ile tane inceltme işlemi uygulanmış alaşımda Al2Cu fazının kum kalıba dökülen alaşım sisteminde daha fazla olduğu belirlenmiştir.

Anahtar Kelimeler:

Al-Si-Cu alaşımı, modifikasyon, tane inceltme

The Effect of Modification and Grain Refining on Microstructure and Mechanical Properties of AlSiCu (LM24) Aluminum Alloy

The modification process with Strontium (Sr) and grain refining process with Al5TiB were applied to AlSiCu alloy in this study. AlSiCu alloy was produced with metal mould and sand mould casting methods after applying modification process with approximately 150-200 ppm Sr and grain refining process with 0.75% and 1.5% Al-5TiB. Microstructure analyses were evaluated by optical microscope (OM) and scanning electron microscope (SEM / EDS analysis), and mechanical properties by tensile test and hardness measurements. As a result, Al-Si eutectic in AlSiCu alloy which was casted into metal mould was found to be more homogeneous and finely dispersed in accordance with optical microscope (OM) analyses. It was observed that the morphology of Al-Si eutectic changed by Sr modification. It was seen with the addition of Al5TiB that dendrites in structure were more regular in the alloy casted into metal mould and yet the amount of space increased. When it was examined the images of the scanning electron microscope (SEM) of the alloys which were casted into metal and sand moulds and to which grain refining process was applied, the Al2Cu phase was determined to be more in the alloy system casted into sand mould.

Keywords:

Al-Si-Cu alloys, modification, grain refinement,

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