Notched tensile strength of SP-700 laser welds

Notched tensile tests were performed to evaluate the influence of post-weld heat treatments (PWHTs) on the notched tensile strength (NTS) of two α + β titanium alloy welds. The results indicated that SP-700 laser welds were notch brittle unless a high PWHT temperature, e.g. 760 °C, was applied. The lowest NTS was associated with the peak-aged weld, which was aged at 482 °C for 1 h. In contrast, Ti-6Al-4V welds did not exhibit notch sensitivity in the as-welded or in the PWHT conditions. The reduced plasticity due to the strengthening of fine α in the β matrix account for the observed notch brittleness of the SP-700 laser welds. Increasing the PWHT temperature associated with coarsening the α + β structure reduced the notch sensitivity of SP-700 laser welds.