TY - JOUR
T1 - Progress in understanding of intrinsic resistance to shear-mode fatigue crack growth in metallic materials
AU - Vojtek, Tomáš
AU - Pokluda, Jaroslav
AU - Hohenwarter, Anton
AU - Pippan, Reinhard
PY - 2015/10/4
Y1 - 2015/10/4
N2 - Recently made experiments allowed measurement of effective data (free of crack tip shielding) and enabled a better understanding of intrinsic behaviour of shear-mode cracks. Influence of crystal structure and microstructure was distinguished. Experimental results for niobium showed that growth micromechanisms and effective thresholds (ΔKIIeff,th ≈ 1.0 MPa m1/2, ΔKIIIeff,th ≈ 1.4 MPa m1/2) of modes II and III cracks were different, which was also observed in other metals. Validity of the simple formula for mode II effective threshold for single-phase metals based on the dislocation emission model was confirmed. The cracks propagated in a coplanar manner along the maximum shear plane, which is a characteristic behaviour for bcc metals. Model of propagation of remote mode III loaded cracks by local mode II advances was confirmed.
AB - Recently made experiments allowed measurement of effective data (free of crack tip shielding) and enabled a better understanding of intrinsic behaviour of shear-mode cracks. Influence of crystal structure and microstructure was distinguished. Experimental results for niobium showed that growth micromechanisms and effective thresholds (ΔKIIeff,th ≈ 1.0 MPa m1/2, ΔKIIIeff,th ≈ 1.4 MPa m1/2) of modes II and III cracks were different, which was also observed in other metals. Validity of the simple formula for mode II effective threshold for single-phase metals based on the dislocation emission model was confirmed. The cracks propagated in a coplanar manner along the maximum shear plane, which is a characteristic behaviour for bcc metals. Model of propagation of remote mode III loaded cracks by local mode II advances was confirmed.
KW - 3D fractography
KW - Effective threshold
KW - Micromechanisms
KW - Modes II and III cracks
KW - Niobium
UR - http://www.scopus.com/inward/record.url?scp=84955269233&partnerID=8YFLogxK
U2 - 10.1016/j.ijfatigue.2016.01.009
DO - 10.1016/j.ijfatigue.2016.01.009
M3 - Article
SN - 0142-1123
VL - 89
SP - 36
EP - 42
JO - International Journal of Fatigue
JF - International Journal of Fatigue
ER -