TY - JOUR
T1 - Crack tip plasticity in single crystal UO 2
T2 - Atomistic simulations
AU - Zhang, Yongfeng
AU - Liu, Xiang Yang
AU - Millett, Paul C.
AU - Tonks, Michael
AU - Andersson, David A.
AU - Biner, Bulent
N1 - Funding Information:
The authors gratefully acknowledge the support of the DOE Nuclear Energy Advanced Modeling and Simulation (NEAMS) Program, under the Fuels Integrated Performance and Safety Code (IPSC) project with work Package No. FTLA11MS0603. Yongfeng Zhang thanks Drs. Blas Uberuaga and Richard Hoagland for beneficial discussions.
PY - 2012/11
Y1 - 2012/11
N2 - The fracture behavior of single crystal uranium dioxide under mode-I loading is studied using molecular dynamics simulations at room temperature. The initial cracks are introduced as elliptical notches on either {1 1 1} or {1 1 0} planes. Two crack tip shielding mechanisms, dislocation emission and metastable phase transformation are identified. Crack extension is observed for cracks residing on {1 1 1} plane only. The dislocations have a Burgers vector of 〈1 1 0〉/2 and glide on {1 0 0} planes. Two metastable phases, Rutile and Scrutinyite, are identified during the phase transformation, and their relative stability is confirmed by separate density-functional-theory calculations. Examination of stress field near the crack tips reveals that dislocation emission is not as an effective shielding mechanism as the phase transformation. The formation of new phases may effectively shield the crack if all phase interfaces formed near the crack tips are coherent, as in the case of cracks residing on {1 1 0} planes.
AB - The fracture behavior of single crystal uranium dioxide under mode-I loading is studied using molecular dynamics simulations at room temperature. The initial cracks are introduced as elliptical notches on either {1 1 1} or {1 1 0} planes. Two crack tip shielding mechanisms, dislocation emission and metastable phase transformation are identified. Crack extension is observed for cracks residing on {1 1 1} plane only. The dislocations have a Burgers vector of 〈1 1 0〉/2 and glide on {1 0 0} planes. Two metastable phases, Rutile and Scrutinyite, are identified during the phase transformation, and their relative stability is confirmed by separate density-functional-theory calculations. Examination of stress field near the crack tips reveals that dislocation emission is not as an effective shielding mechanism as the phase transformation. The formation of new phases may effectively shield the crack if all phase interfaces formed near the crack tips are coherent, as in the case of cracks residing on {1 1 0} planes.
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U2 - 10.1016/j.jnucmat.2012.06.044
DO - 10.1016/j.jnucmat.2012.06.044
M3 - Article
AN - SCOPUS:84864108193
SN - 0022-3115
VL - 430
SP - 96
EP - 105
JO - Journal of Nuclear Materials
JF - Journal of Nuclear Materials
IS - 1-3
ER -