Akademik Veri Yönetim Sistemi
Tezin Türü: Yüksek Lisans
Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Metalurji ve Malzeme Mühendisliği Bölümü, Türkiye
Tezin Onay Tarihi: 2018
Öğrenci: ŞAHİN GÖREN
Danışman: RIZA GÜRBÜZ
Özet:In this study, effects of heat treatment parameters on microstructure, hardness and fatigue behavior of 15-5 precipitation hardenable stainless steels have been examined. Heat treatments have been conducted in three different steps homogenization, solutionizing and aging treatment at different temperatures and times. Microstructural analysis in terms of grain size and chemical composition analysis have been performed by optical and scanning electron microscope (SEM). Then, hardness measurements were applied for all heat treated specimens. Fatigue tests have been conducted at negative stress ratio (R) equal to -1 under constant amplitude cyclic loading for selected group of heat treated specimens. Fatigue test results have been evaluated according to AGARD-AG-292 and ISO 12107 standards in order to see the effect of heat treatment parameters on fatigue limit of the 15-5 precipitation hardenable stainless steels. Fatigue limit was determined as stress level at 107 cycles on stress vs. cycle (S-N) curve. It was also calculated by using staircase method in order to verify the fatigue limit that was found as stress level at 107 cycles on S-N curve. Higher hardness and fatigue limit were achieved for aging treatment at 4800C for 1h and 4000C for 70h compared to aging treatment at 5500C for 4h. The measurements and test results show that by changing heat treatment parameters, hardness and fatigue limit of 15-5 precipitation hardenable stainless steel can be increased.