Fatigue response and micromechanisms of crack initiation in Ti-10V-2Fe-3Al titanium alloy

Conference · Thu Jul 01 04:00:00 EDT 1999

OSTI ID:20013315

Shankar, P S; Ravichandran, K S

Fatigue response of three beta annealed microstructures of Ti-10V-2Fe-3Al, having comparable strength levels was studied. The effect of microstructure on fatigue resistance has been rationalized in terms of size, location and origin of fatigue crack initiation site. The resistance to fatigue crack growth was almost similar in all microstructures. However, the {sigma}{sub max}-N{sub f} behavior of {omega}-aged microstructures was relatively poor compared to the furnace cooled and {alpha}-aged microstructures. In all these microstructures, subsurface crack initiation was observed at low stress levels while surface crack initiation was observed at higher stress ranges. Subsurface crack initiation appears to occur by a process of crystallographic cleavage. The mechanism of cleavage seems to determine the fatigue crack initiation site size. The {omega}-aged microstructure exhibited a stress dependence on the crack initiation site size. On the contrary, the crack initiation site size is independent of the stress range in the furnace cooled and {alpha}-aged microstructures. This appears to extend the crack initiation life in both these microstructures, relative to the {omega}-aged microstructure.

• Research Organization: Univ. of Utah, Salt Lake City, UT (US)
• Sponsoring Organization: US Department of the Air Force
• OSTI ID: 20013315
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
36 MATERIALS SCIENCE
AIRCRAFT
ALUMINIUM ALLOYS
CRACK PROPAGATION
EXPERIMENTAL DATA
FATIGUE
IRON ALLOYS
TENSILE PROPERTIES
TITANIUM BASE ALLOYS
VANADIUM ALLOYS
WEIGHT