TY - JOUR

T1 - Role of nanotwins on fatigue crack growth resistance

T2 - Experiments and theory

AU - Alkan, Sertan

AU - Chowdhury, Piyas

AU - Sehitoglu, Huseyin

AU - Rateick, Richard G.

AU - Maier, Hans J.

PY - 2015/11/21

Y1 - 2015/11/21

N2 - The study of near-threshold fatigue crack growth has long remained an empirical field due principally to the highly microstructure-sensitive nature thereof. The primary challenges have been to forward physical model(s) informed by the governing micromechanism(s), which would be able to predict the experimental behaviors devoid of empiricism. Today, we have sophisticated experimental techniques (e.g. digital image correlation, electron microscopy) as well as atomistic simulation tools (e.g. molecular dynamics) at our disposal to finally revisit the century old fatigue problem in the light of physical phenomena therein. This paper is geared towards achieving such a feat with a very special type of materials, nano-twinned alloys, as the candidate materials, which are of great recent interest due to their reportedly superior damage properties. Specifically, we investigate how the microstructural features (e.g. slip transfer mechanism at coherent twin boundaries, twin thickness/spacing, frictional stress, pre-existent near-tip slip density) can be modulated to improve the damage resistance. The results suggest that these parameters considerably affect the crack propagation impedance (as quantified in terms of ΔKeffth). A thorough discussion of the current findings and the most recent literature developments in this regard are provided.

AB - The study of near-threshold fatigue crack growth has long remained an empirical field due principally to the highly microstructure-sensitive nature thereof. The primary challenges have been to forward physical model(s) informed by the governing micromechanism(s), which would be able to predict the experimental behaviors devoid of empiricism. Today, we have sophisticated experimental techniques (e.g. digital image correlation, electron microscopy) as well as atomistic simulation tools (e.g. molecular dynamics) at our disposal to finally revisit the century old fatigue problem in the light of physical phenomena therein. This paper is geared towards achieving such a feat with a very special type of materials, nano-twinned alloys, as the candidate materials, which are of great recent interest due to their reportedly superior damage properties. Specifically, we investigate how the microstructural features (e.g. slip transfer mechanism at coherent twin boundaries, twin thickness/spacing, frictional stress, pre-existent near-tip slip density) can be modulated to improve the damage resistance. The results suggest that these parameters considerably affect the crack propagation impedance (as quantified in terms of ΔKeffth). A thorough discussion of the current findings and the most recent literature developments in this regard are provided.

KW - Damage tolerance

KW - Microstructure

KW - Nanoscale twin

KW - Residual dislocation

KW - Threshold stress intensity

UR - http://www.scopus.com/inward/record.url?scp=84948844899&partnerID=8YFLogxK

U2 - 10.1016/j.ijfatigue.2015.11.012

DO - 10.1016/j.ijfatigue.2015.11.012

M3 - Article

AN - SCOPUS:84948844899

VL - 84

SP - 28

EP - 39

JO - International journal of fatigue

JF - International journal of fatigue

SN - 0142-1123

ER -