The influence of porosity on the fatigue crack growth behavior of Ti–6Al–4V laser welds

Microstructure and Mechanical Properties of Laser Beam Welded Joints between Fine‐Grained and Standard Ti‐6Al‐4V Sheets Subjected to Superplastic Forming

“…8. Studies on LBW of the Ti-6Al-4V alloy without filler wire showed that the lowest hardness values were found for the Ti-6Al-4V BM, and the highest hardness values were found for wedge-shaped welds (Squillace et al, 2012;Tsay and Tsay, 1997;Torster et al, 1999). Squillace et al, 2012, studied how the laser heat input affected the Ti-6Al-4V weld microhardness and found that the microhardness increased with the welding speed, which was controlled by increasing the cooling rate and by decreasing the heat input.…”

“…The successful fabrication of Ti-6Al-4V lightweight structures requires efficient joining technologies and the availability of data on the mechanical and microstructural properties of welded titanium structures. In recent years, a variety of welding processes for Ti-6Al-4V have been developed, such as gas tungsten arc welding (GTAW) Oh et al, 2003), electron beam welding (EBW) Oh et al, 2003;Li et al, 2011;Saresh et al, 2007;Wu, 2012, Wanjara et al 2005), laser beam welding (LBW) Cao and Jahazi, 2009;Torster et al, 1999;Pei-quan, 2012;Squillace et al, 2012;Tsay and Tsay, 1997;Wang et al 2003;Jianxun et al, 2012;Rai et al, 2007) and hybrid joining processes, e.g., laser gas metal arc welding (Petersen, 2012). From an industrial perspective, the LBW technique can be used to realise high working speeds and is the most cost-efficient and easy controllable joining process for the production of Ti-6Al-4V parts (Rosell, 2013;Vallhagen, 2013).…”

“…Laser beam welded Ti-6Al-4V joints exhibit a balanced microstructure and high tensile strength (Squillace et al, 2012;Cao and Jahazi, 2009;Torster et al, 1999;Pei-quan, 2012;Wang et al, 2003). However, little research has been conducted on how the microstructure of laser beam welded Ti-6Al-4V joints affects their fatigue behaviour Squillace et al, 2012;Tsay and Tsay, 1997).…”

Effect of Postweld Heat Treatment on Microstructure, Hardness, and Tensile Properties of Laser-Welded Ti-6Al-4V

“…In addition, the hydrogen-rich liquid in the center region has a low temperature at the late stage of solidification, and hence, the gas cannot effectively escape, leading to the presence of porosity in the center of the welds. [13] However, keyhole collapse may also contribute to porosity formation [7] if a sudden drop in vapor pressure results in slumping of the molten metal into the keyhole. [31] In particular, keyhole stability is related to the welding speed and the balance in forces acting on the keyhole wall (mainly vapor pressure and surface tension).…”

“…In addition, laser welding of titanium alloys with local shielding gas protection offers manufacturing flexibility as well as ease of automation. [5][6][7] Of the various titanium grades, Ti-6Al-4V has been reported to have good weldability, but its strength, ductility, and toughness may be significantly varied, depending on the thermal cycling history during manufacturing. [8] Despite the extensive amount of literature on the weldability of Ti-6Al-4V, the effect of postweld heat treatment (PWHT) on the mechanical performance of Ti-6Al-4V laser welds has not been well understood.…”