FORMABILITY CAPABILITIES AND MECHANICAL PROPERTIES OF TITANIUM TAILOR-WELDED BLANKS

Titanium alloys have many applications in aerospace, nuclear and automotive industries and in most parts are in sheet form and require joints of high integrity to meet the design requirements and achieve reliable welds. For weight and cost reduction, the technology of tailor-welded blanks (TWBs) is a promising technology in various components. TWBs are usually semi-finished metallic sheets made of different strengths, materials, and/or thicknesses and a forming process is often needed to manufacture the final components. In this paper, Grade-2 and Grade-5 titanium alloy sheets (Ti-TWBs) were laser welded and subjected to a forming process in U-profile geometry at elevated temperatures. The deformation behaviors of the weld joints after forming process were analyzed by mechanical tests such as tensile and hardness tests. The formability of the welded blanks is assessed based on variations in the geometric changes related to the springback angles. The results showed that there was significant increase in tensile strength with forming temperature increase and the failure mode was changed at 850 °C. The formability of the Ti-TWBs was found to be strongly dependent on the applied process temperatures and forming at 850 °C leads to the lowest springback angle.