Effects of heat treatments on the microstructure and mechanical properties of Nd:YAG laser beam welded Ti6Al4V alloy

Abstract

In the present study, Ti6Al4V titanium alloy plates were joined using Nd:YAG laser beam welding method. Pre- and post-weld heat treatments were applied to laser welded joints. After welding stress relieving, solution heat treatment and ageing were also applied to preheated laser welded samples. Effects of heat treatment conditions on microstructure and mechanical properties of laser beam welded joints were studied. The results showed that the aged samples were found to be made of coarsened grains compared to microstructures of non-aged samples. There were increases in ductility and toughness of samples applied to ageing increased, while hardness and tensile strength of non-aged samples were higher.

Keywords

• Titanium alloy,laser welding,heat treatment,microstructure,mechanical properties

Nd:YAG lazer kaynağı ile birleştirilen Ti6Al4V alaşımının mikroyapı ve mekanik özelliklerine ısıl işlemlerin etkileri

Abstract

Bu çalışmada, Ti6Al4V titanyum alaşımı levhalar Nd:YAG lazer kaynak yöntemiyle birleştirilmiştir. Lazer kaynaklı birleştirmelere kaynak öncesi ve sonrası ısıl işlem uygulanmıştır. Ön ısıtma uygulanan lazer kaynaklı numunelere, kaynak sonrası gerilim giderme, solüsyon ısıl işlemi ve yaşlandırma ısıl işlemi uygulanmıştır. Isıl işlem şartlarının, lazer kaynaklı birleştirmelerin mikroyapı ve mekanik özelliklerine etkileri incelenmiştir. Deney sonuçları incelendiğinde, yaşlandırma ısıl işlemi uygulanan numunelerin mikroyapısı yaşlandırma uygulanmayan numunelere göre daha kaba taneli bir yapıdan oluşum gösterdiği gözlenmiştir. Yaşlandırma uygulanan numunelerde süneklik ve tokluk değerlerinde artış gözlenirken yaşlandırma uygulanmayan numunelerin sertlik ve çekme dayanımlarında artış tespit edilmiştir.

Keywords

• Titanyum alaşımı,lazer kaynak,ısıl işlem,mikroyapı,mekanik özellikler

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