Heat treatment of laser-additive welded Ti2AlNb joints: Microstructure and tensile properties

Effect of pre-heating and post-weld heat treatment on structure and mechanical properties of laser beam-welded Ti2AlNb-based joints

“…The crack formation was most likely associated with the transgranular cleavage fracture within the β-grain. The fracture mode found here is consistent with other results obtained for the welded joints of Ti alloys with a β structure [21].…”

“…5e). A similar structure of HAZ in Ti 2 AlNb-based alloys was also reported by Wang et al [27] and Zhang et al [21]. In HAZ1, large β-phase grains were observed (Fig.…”

“…FZ predominantly consisted of the β-phase. The cooling rate was high enough to retain the β-phase structure in FZ and mostly suppress the Oand α 2 -phases formation during solidification of the melted material that can also be associated with the effect of a high Nb content [21]. However, at 800 • C, less than 10% of the O-phase lamellae were detected within FZ (Supplementary Materials, Fig.…”

“…In HAZ2 the globular α 2 -phase was partially preserved (Fig. 5d) because the heating temperatures were not sufficient to the complete α 2 →β transformation [21]. In comparison to BM, HAZ3 consisted of β + O + α 2 (Fig.…”

“…For instance, pre-heating brittle intermetallic alloys to 600 • C and above eliminates the welding crack formation in the weld zone [20]. Hence, high-quality laser-welded Ti 2 AlNb joints might be obtained due to PWHT [21].…”