DETERMINATION OF PROCESS MAP FOR HOT FORMING OF Ti-6Al-4V
| dc.contributor.advisor | Şimşir, Caner | |
| dc.contributor.author | Demirkol, Yasin | |
| dc.date.accessioned | 2022-02-24T11:08:44Z | |
| dc.date.available | 2022-02-24T11:08:44Z | |
| dc.date.issued | 2022-02-24 | |
| dc.description | Titanium alloys are used in the field of aviation, turbine blades, gas turbines and engine parts, propellers and many other parts because of their resistance to corrosion as well as their high strength to weight ratio. However, in order to take advantage of these properties, titanium alloys having low ductility at room temperature require high temperature forming techniques which have inherent disadvantages. Hot forging is the most common method for manufacturing these components. Titanium hot forging is more complicated than conventional steel forging due to many reasons: flow instabilities that may occur during forging, macro-micro cracks, static and dynamic strength loss due to melting at grain boundaries and heterogeneous microstructure and alpha layer formation due to air interaction are most common problems. More important than these, the microstructure formed during the titanium alloys forging cannot be repaired by the post-forging heat treatment as opposed to many steels. For this reason, titanium forging must be designed as a "thermo mechanical-metallurgical process", not only as a forming process. In this work, the material data required for designing the hot forging process of the Ti 6Al-4V alloy to satisfy the above conditions was obtained by experimental methods. A wide range of temperature and strain rate controlled compression tests was performed to find the material law parameters that determine the behavior of the material in the plastic region. A "Process Map" was generated which restricts the amount of temperature, deformation amount and speed to obtain forged products without any problems and desired microstructure. | |
| dc.description | ÖZ: Titanyum alaşımları, hafif ve mukavemetli olmalarının yanı sıra korozyona karşı dirençleri sebebiyle havacılık alanında, türbin bıçakları, gaz türbin ve motor parçaları, pervaneler gibi birçok parçanın imalatında kullanılmaktadır. Fakat, bu avantajlardan yararlanabilmek oda sıcaklığındaki düşük süneklikleri nedeniyle, titanyum alaşımlarının genellikle kendine özgü başka sıkıntıları olan yüksek sıcaklık hacimsel ve sac şekillendirme yöntemlerine ihtiyaç duyulmaktadır. Sıcak dövme işlemi bu bileşenlerin imalatı için en yaygın kullanılan yöntemdir. Titanyum sıcak dövme işlemi geleneksel çeliklerin dövme işlemine göre birçok sebepten dolayı daha karmaşıktır: Dövme sırasında oluşabilen akış kararsızlıkları, makro/mikro çatlaklara sebep olması, tane sınırlarında erime ve heterojen içyapı nedeniyle statik ve dinamik mukavemet kaybı, havayla etkileşimden dolayı alfa tabakası oluşumu en sık karşılaşılan problemlerdir. Bunlardan daha önemlisi titanyum dövme sırasında oluşan içyapı birçok çeliğin aksine dövme sonrası yapılan ısıl işlemde onarılamamaktadır. Bu nedenle titanyum dövme işlemi sırf bir şekillendirme işlemi olarak değil, ürüne “özellik kazandırılan” bir termo-mekanik-metalurjik bir süreç olarak tasarlanmalıdır. Bu çalışmada, Ti-6Al-4V alaşımının sıcak kalıp dövme işleminin yukarıdaki belirtilen şartları sağlayacak şekilde tasarımı için gerekli olan malzeme verisi, deneysel yöntemlerle elde edilmiştir. Malzemenin plastik bölgedeki davranışını belirleyen malzeme yasası parametrelerini belirlemek için geniş yelpazede sıcaklık ve genleme hızı kontrollü basma testleri gerçekleştirilmiştir. Hatasız, istenilen içyapıda dövme ürününün elde edilmesi için deformasyon miktarı ve hızlarını kısıtlayan “Süreç Haritası” elde edilmiştir. | |
| dc.description.abstract | Titanium alloys are used in the field of aviation, turbine blades, gas turbines and engine parts, propellers and many other parts because of their resistance to corrosion as well as their high strength to weight ratio. However, in order to take advantage of these properties, titanium alloys having low ductility at room temperature require high temperature forming techniques which have inherent disadvantages. Hot forging is the most common method for manufacturing these components. Titanium hot forging is more complicated than conventional steel forging due to many reasons: flow instabilities that may occur during forging, macro-micro cracks, static and dynamic strength loss due to melting at grain boundaries and heterogeneous microstructure and alpha layer formation due to air interaction are most common problems. More important than these, the microstructure formed during the titanium alloys forging cannot be repaired by the post-forging heat treatment as opposed to many steels. For this reason, titanium forging must be designed as a "thermo mechanical-metallurgical process", not only as a forming process. In this work, the material data required for designing the hot forging process of the Ti 6Al-4V alloy to satisfy the above conditions was obtained by experimental methods. A wide range of temperature and strain rate controlled compression tests was performed to find the material law parameters that determine the behavior of the material in the plastic region. A "Process Map" was generated which restricts the amount of temperature, deformation amount and speed to obtain forged products without any problems and desired microstructure. | |
| dc.identifier.uri | http://hdl.handle.net/20.500.11905/592 | |
| dc.language.iso | en | |
| dc.subject | manufacturing engineering | |
| dc.title | DETERMINATION OF PROCESS MAP FOR HOT FORMING OF Ti-6Al-4V | |
| dc.title.alternative | Ti-6Al-4V ALAŞIMININ SICAK ŞEKİLLENDİRMESİ İÇİN SÜREÇ HARİTASININ BELİRLENMESİ | |
| dc.type | Thesis | |
| dspace.entity.type |