T. Mohandas et al., Effect of post-weld heat treatment on fracture toughness and fatigue crackgrowth behaviour of electron beam welds of a titanium (alpha+beta) alloy, FATIG FRACT, 23(1), 2000, pp. 33-38
Citations number
20
Categorie Soggetti
Material Science & Engineering
Journal title
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
The effects of a post-weld heat treatment on the fracture toughness and fat
igue crack growth behaviour of electron beam welds of an alpha + beta titan
ium alloy, Ti-6.5Al-1.9Zr-0.25Si have been studied. Welds in the stress-rel
ieved condition exhibited poor fracture toughness due to poor energy absorb
ing capacity of the thin alpha and alpha' phases. Post-weld heat treatment
which resulted in the decomposition of a' to alpha + beta and the coarsenin
g of intragranular and intergranular alpha resulted in improved toughness.
This improvement in the toughness is related to improved ductility leading
to crack blunting, crack path deviation at the thick intragranular and inte
rgranular a phase. Fatigue crack growth resistance of welds was superior to
the base metal in the alpha + beta heat-treated condition. The superior cr
ack growth resistance of the welds is due to the acicular alpha microstruct
ure which results in a tortuous crack path and possible crack closure arisi
ng from crack path tortuosity.