Mg. Mendiratta et al., NOTCH FRACTURE IN GAMMA-TITANIUM ALUMINIDES, Metallurgical and materials transactions. A, Physical metallurgy andmaterials science, 27(12), 1996, pp. 3903-3912
The notch fracture behavior of two gamma-titanium aluminide alloys, ha
ving duplex and fully lamellar microstructures, has been investigated
as a function of notch geometry and test temperature. The unnotched te
nsile properties and notch fracture loads are used to perform finite e
lement analysis (FEA) to determine triaxial tensile stresses and effec
tive plastic strains in the vicinity of notch roots. These results, to
gether with fractographic examinations of notch failures, indicate tha
t a crack nucleates in the triaxial tensile field when the effective v
on Mises stress just exceeds the uniaxial tensile yield stress. The hi
gh tensile stress component then propagates the nucleated microcrack t
o failure with local stress intensity reaching the toughness of the ma
terial. Thus, both plasticity and high tensile stress are required to
cause notch failure.