Notched tensile fracture of Ti–4.5Al–3V–2Fe–2Mo welds at elevated temperatures

Abstract

Notched tensile tests of Ti–4.5Al–3V–2Fe–2Mo welds with distinct post-weld heat treatments (PWHTs) were carried out at 150, 300, and 450 °C. The results were also compared with those of mill-annealed base metal (the MB specimen) tested at the same conditions. The as-welded (AW) specimen exhibited notch brittleness even when tested at 450 °C, partly due to a fast age-hardening response at the test temperature. In contrast, the weld with PWHT at 482 °C exhibited severe notch brittleness at room temperature but showed an increase in strength and ductility as the temperature increased. In general, the weld with PWHT at 704 °C (the W-704 specimen), AW and MB specimens displayed reduced notched tensile strength (NTS) with increasing temperature. At elevated temperatures, the W-704 specimen with coarse α + β structures in a basket-weave form also demonstrated superior NTS to the MB specimen with banded α + β structures.