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Highlights: [•] The overlapping factor of pulsed laser welding is used to help understand the correlation between welding parameters and the quality of pulsed laser welded joint. [•] Increasing overlapping factor is an effective way of minimizing or even totally eliminating pores. [•] A way to evaluate the porosity susceptibility of a specific welding condition prior to actual welding process is presented. [•] The microstructure and microhardness gradients decrease with the increase in overlapping factor. [ABSTRACT FROM AUTHOR]

In this study, the influence of weld cross-sectional profiles and microstructure, under different welding conditions, was investigated on the mechanical properties of pulsed Nd:YAG laser-welded joint of Ti6A14V alloy. The V- and H-shaped weld cross-section profiles were obtained under low and high heat input, respectively. The microstructure in the fusion zone (FZ) of V- and H-shaped welded joint consisted of a fine acicular martensitic α′ solidification structure within the prior-β grains, responsible for the maximum hardness in the FZ. Tensile tests revealed that the V-shaped welded joint fractured at the near heat-affected zone (HAZ)/base metal (BM) interface, but the H-shaped welded joint fractured in the BM. Furthermore, the tensile strength of the V-shaped welded joint was lower than that of the H-shaped welded joint. This was attributed to the fact that the heterogeneity of strain distribution at the interface of HAZ and BM of the V-shaped welded joint was greater than that of the H-shaped welded joint during tensile process. [ABSTRACT FROM AUTHOR]

Highlights: [•] The influence of the great microstructure gradient on fatigue damage behavior of Ti6Al4V LBW joint was studied. [•] The fatigue residual strength and fatigue crack growth rate of Ti6Al4V sheets and LBW joint were investigated comparably. [•] Effects of microstructure on fatigue fracture surfaces properties of Ti6Al4V sheets and LBW joint were analyzed comparably. [Copyright &y& Elsevier]

Abstract: This paper reports on a study aiming at comparing properties of the Ti6Al4V titanium alloy joints between pulsed Nd:YAG laser welding and traditional fusion welding. To achieve the research purpose, Ti6Al4V titanium alloy plates with a thickness of 0.8mm were welded using pulsed Nd:YAG laser beam welding (LBW) and gas tungsten arc welding (TIG), respectively. Residual distortions, weld geometry, microstructure and mechanical properties of the joints produced with LBW and TIG welding were compared. During the tensile test, with the aid of a high speed infrared camera, evolution of the plastic strain within tensile specimens corresponding to LBW and TIG welding were recorded and analyzed. Compared with the TIG, the welded joint by LBW has the characters of small overall residual distortion, fine microstructure, narrow heat-affected zone (HAZ), high Vickers hardness. LBW welding method can produce joints with higher strength and ductility. It can be concluded that Pulsed Nd:YAG laser welding is much more suitable for welding the thin Ti6Al4V titanium alloy plate than TIG welding. [Copyright &y& Elsevier]