YILMAZ, Ramazan Sakarya Üniversitesi - Teknoloji Fakültesi - Metalurji ve Malzeme Mühendisliği Bölümü, Turkey , ÖZYÜREKZ, ursun Karabük Üniversitesi - Teknoloji Fakültesi - İmalat Mühendisliği Bölümü, Turkey , KİBAR, Erkan Sakarya Üniversitesi - Fen Bilimleri Enstitüsü - Metal Eğitimi Anabilim Dalı Esentepe Kampüsü, Turkey

THE EFFECTS OF RETROGRESSION PARAMETERS ON HARDNESS AND WEAR BEHAVIOURS OF 7075 ALUMINIUM ALLOYS

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In this study, retrogression and re-aging (RRA) treatments on 7075 aluminium alloys has been carried out. 7075 aluminium alloys that were already T6 temper applied were retrogressed at the range of 180-260oC for durations between 15-75 minutes and later re-aged in T6 aging condition of 120°C for 24 hours. The effects of retrogression temperature and times on the hardness and wear properties were investigated. Wear tests were carried out by using machine that is for pin on disc technique. Worn surfaces of the samples after tests were also examined by scanning electron microscopy (SEM) for better understanding of wear mechanism. Experimental studies show that retrogression treatments parameters such as temperatures and times have great effects on wear resistance of 7075 aluminium alloys. Close relationship between the hardness and wear resistance values were seen in those alloys. Variations in hardness values were all depend on retrogression temperatures and times. The alloy retrogressed at 220°C for 60 minutes showed the highest hardness values and wear resistance.

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Aluminium , aging , 7075 , wear , hardness , retrogression and re , aging (RRA)

Journal Of The Faculty Of Engineering an‎d Architecture Of Gazi University

438