Effect of TIG-Welding on the Structure and Mechanical Properties of Low-Cost Titanium Alloy Ti-2.8Al-5.1Mo-4.9Fe Welded Joints

Abstract

Titanium alloys are widely used in aerospace, automotive, biomedical and marine engineering due to their good hot and cold processing properties, fracture toughness, high specific strength and good deformability. Nevertheless, titanium is also characterized by very high production costs, which are approximately 6 times and 30 times higher, respectively, in comparison to those to obtain the same quantity of aluminum or steel relegating titanium to high demanding sectors. One possible way to reduce the cost of titanium is to use cheaper alloying elements instead of vanadium or niobium to stabilize the body-centred-cubic (B.C.C) β-phase. TIG-welding of high-strength low-cost pseudo-β titanium alloys is complicated, primarily due to the high content of alloying elements, such as iron, molybdenum, as well as the use of oxygen as an alloying elements. By the correct choice of welding modes in most cases, it is possible to obtain welded joints of high-strength pseudo-β titanium alloys with good microstructure and mechanical properties. To study the influence of TIG welding on the structure and mechanical properties of low-cost titanium alloy Ti–2.8Al–5.1Mo–4.9Fe, two types of TIG-welding chosen: standard fusion TIG welding and TIG welding on the thin flux layer.