Funda Gül Koç, Mustafa Çöl, Tanju Çeliker

Al-Zn-Mg-Cu alaşımlarının su verme hassasiyeti

Al-Zn-Mg-Cu alüminyum alaşımları sahip oldukları düşük yoğunluk, yüksek mukavemet, sertlik, tokluk ve korozyon direnci özelliklerinden dolayı havacılık ve uzay endüstrisinde geniş bir kullanım alanına sahiptir. Bu çalışmada, 7075 serisi alüminyum alaşımının su verme hassasiyeti alın su verme yöntemi kullanılarak incelenmiştir. Numuneye 480 °C’de 3 sa. süreyle çözeltiye alma işlemi uygulandıktan hemen sonra alın su verme test düzeneğinde oda sıcaklığındaki su ile bir uçtan soğutma işlemi uygulanmıştır. Soğutma işlemi esnasında numunenin boyuna kesiti boyunca meydana gelen soğuma hızındaki değişimler K tipi termo-elemanlar vasıtasıyla eş zamanlı olarak ölçülmüştür. Su verme işlemi sonrası numuneye 120 °C’de 24 sa. süre ile suni yaşlandırma işlemi uygulanmıştır. Su verilen uçtan uzaklaştıkça malzemenin sertlik, elektriksel iletkenlik ve mikroyapı özeliklerinde meydana gelen değişimler incelenmiştir.

Anahtar Kelimeler:

Su verme hassasiyeti, Al-Zn-Mg-Cu alaşımları, Sertlik, Elektriksel iletkenlik, Mikroyapı

Quench sensitivity of Al-Zn-Mg-Cu alloys

Al-Zn-Mg-Cu aluminum alloys are extensively used in aviation and aerospace industries for their high strength, hardness, toughness and corrosion resistance. In this study, quench sensitivity of 7075 series aluminum alloy was investigated by using end quench test. Specimens were solution treated at 480 °C for 3 hours and then the specimens were immediately transferred to the end quenching rig (<5s). Changes in the temperature of the specimen during the quenching process were measured by using type K thermocouples. Quenched specimen was subjected to artificial aging at 120 °C for 24 hours. The changes of hardness, electrical conductivity and microstructure properties of the material as the distance from quenched end of bar increases were investigated.

Keywords:

Quench sensitivity, Al-Zn-Mg-Cu alloys, Hardness, Electrical conductivity, Microstructure,

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