1992 Volume 10 Issue 1 Pages 120-124
Effect of aging treatment on hardening characteristics in HAZ of Ti-15V-3Cr-3Sn-3Al titanium alloy was investigated by means of transmission electron microscopy and X-ray diffraction technique.
As the aged Ti-15V-3Cr-3Sn-3Al alloy was welded by using DCRP-TIG welding procedure, the decrease of the hardness occurred in the heat-affected zone, because of the solution of α phase. The hardness in the HAZ was considerably higher than that of the base metal, as the welded sample was aged at 773 K after welding.
Maximum hardness after aging treatment increased with increasing solution treatment temperature. The precipitation of α phase occurred, as the specimens were aged at 573, 673, 773 K after solution treatment. The precipitation amount of α phase increased with increasing solution temperature at any aging temperature.
The high solution treatment temperature also caused homogeneous precipitation and fine precipitation of α phase during aging by means of transmission electron microscopy.
Consequently, the high hardness was due to the fine precipitation of α phase.
