The effect of post-weld heat treatment on the microstructure and notched tensile fracture of Ti-15V-3Cr-3Al-3Sn to Ti-6Al-4V dissimilar laser welds
Journal
Materials Science and Engineering A
Journal Volume
653
Pages
139-146
Date Issued
2016
Author(s)
Abstract
A CO2 laser was applied for dissimilar welding of Ti-15V-3Cr-3Al-3Sn (Ti-15-3) to Ti-6Al-4V (Ti-6-4) alloys. The microstructures and notched tensile strength (NTS) of the dissimilar welds were investigated in the as-welded and post-weld heat treatment (PWHT) conditions, and the results were compared with Ti-6-4 and Ti-15-3 homogeneous laser welds with the same PWHT. The results indicated that predominant α″ with a few α and β phases was formed in the as-welded fusion zone (FZ). Furthermore, the FZ hardness was susceptible to the PWHT and showed a plateau for the specimens aged in the temperature range from 426 to 482°C/4h. In comparison with the homogeneous Ti-15-3 weld under the same PWHT conditions, the dilution of Ti-15-3 with Ti-6-4 caused a slight increase in the Al equivalent (AlEQ) of the FZ, resulting in a further rise in FZ hardness. With the PWHT at/below 538°C, the dissimilar welds were associated with low NTS or high notch brittleness.
SDGs
Type
journal article