Düşük frekanslı mekanik titreşimin AI-%7.15 Si alaşımın makro ve mikro yapısına etkisi

Değişik frekanslarda (15,21.7, 31.7,41.7Hz) ve genliklerdeki (0.125, 0.250, 0.375, 0.5mm) titreşim modife edilmemiş ve metalik sodyum ile modifie edilmiş Al-%7.15Si alaşımına katılaşma sırasında uygulanmıştır. Düşük frekanslı titreşimin tane boyutu, çekme boşluğu (shrinkage pipe) ve ötektik silisyum üzerindeki etkisi metalografik gözlemleme ve nicel ölçme tekniği ile incelenmiştir. Elde edilen sonuçlar; (1) İngottaki çekme boşluğu 0.125-0.375mm genlik ve 31.7-41.7Hz frkanslarda azalır, fakat 0.5mm genlik ve 31.7-41.7Hz frekanslarda artar, (2) Sıvının titreşim zamanı çekme boşluğu üzerinde etkilidir, (3) titreşimin frekansı ve genliği arttıkça tane boyutu küçülmektedir, (4) Titreşim artan frekansa ve genliğe bağlı olarak ötektik lamel ve yosun silisyumu kabalaştırmıştır. (5) Kabalaşma titreşim zamanına da bağlıdır. (6) Alaşımın titreşim altında katılaştırılması hücre boyutunu değiştirmemiştir.

Effect of low frequency vibration on macro and micro structures of Al-7.15% Si alloy

Vibration of varying frequencies (15, 21.7, 31.7, 41.7 Hz) and amplitudes (0.125, 0.250, 0.375, 0.5 mm) has been applied to unmodified and metallic sodium modified Al-7.15%Si alloy during solidification. The effect of low frequency vibration on the grain size, shrikage pipe and eutectic silicon were analysed metallographically and quantitatively. Obtained results are; (1) The pipe found in ingot was decreased with vibration at a frequencies 31.7-41.7Hz and amplitudes 0.125-0.375mm, but, it was increased at a frequncies of 31.7-41.7Hz and an amplitude of 0.5mm. (2) Vibration time of liquid was more effective on pipe elimination, (3) Vibration with increasing frequency and amplitude produced grain refinement, (4) Vibration with increasing frequency and amplitude caused coarsening in the eutectic silicon in unmodified and sodium modified Al-7.15%Si alloy, (5) Coarsening also depends on vibration time. (6) Solidification of Al-Si alloy under vibration did not change cell size,

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