Notched Tensile Fracture of Ti–6Al–4V Laser Welds at Elevated Temperatures

Abstract

Notched tensile tests of Ti6Al4V laser welds that were subjected to post-weld heat treatments (PWHTs) at 482 and 704°C were carried out in air at temperatures from 25 to 450°C. The experimental results were also compared with those of the mill-annealed base metal (MB) specimens tested at similar temperatures. Generally, the notched tensile strength (NTS) of the specimens was sensitive to the test temperature. The NTS of laser welds was lower than that of the MB specimen at room temperature, but the trend reversed at 450°C. The presence of thick grain boundary ¡ layers, which promoted intergranular fracture at elevated temperatures, could account for the lowered NTS of the weld after PWHT at 704°C. [

Laser Beam Welding of a Ti–6Al–4V Support Flange for Buy-to-Fly Reduction

“…An increase of hardness resulted in the fusion zone, from 340 HV0.3 in the base metal to average 430 HV0.3 with as high as 443 HV0.3 peak values in the as-welded condition. In agreement with the literature [24], it is worth noting that a decrease of hardness to average 382 HV0.3 in the fusion zone, hence a reduced mismatch with respect to the base metal, has been benefited upon heat treating. Furthermore, based on the step between consecutive indentations (i.e., 150 μm), the extent of the heat-affected zone is deemed to be shorter than 0.3 mm at both sides of the fusion zone and is not considered to be affected by heat treatment.…”

Modelling of Welding Parameters on Bead Geometry in Nd: Yag Laser Welding of Titanium With Ti-6al-7nb Using Response Surface (Rsm)

“…Under optimized processing conditions, the static strength of the laser-welded titanium alloy samples can be close to the original material; however, there are still some processing problems such as lower elongation and corrosion resistance coupled with inferior fatigue properties [4]. The microstructures of α + β titanium alloys play an important role in determining the mechanical properties and fracture behavior of these materials [5]. The weld pool dimensions and weld quality of spot welds produced using a pulsed Nd: YAG laser welding machine depend on various process parameters including the spatial intensity distribution of the incident laser beam, the peak power of the pulse, the pulse energy, the pulse time, and the temporal shape of the beam power during the pulse.…”