Crack propagation in silicates is enhanced in an aqueous environment, which has been suggested to be the result of chemical reactions between water and strained siloxane bonds at the crack tip. To identify the coupled chemical-mechanical mechanisms that govern silicate fracture in the presence of water, molecular dynamics simulations of sub-critical fracture in amorphous silica were performed with classical and reactive forcefields. Slit cracks were introduced into bulk silica models and propagated as mode I fractures. Atomistic stress and energy data was upscaled to corresponding continuum fields via an Irving-Kirkwood method with Lagrangian kernel estimator in order to calculate the J-integral around the crack tip and identify the fracture toughness. Infiltration of the silica slit crack with reactive water molecules allowed for natural hydroxylation and evaluation of changing fracture toughness in the presence of water.<br/><br/>Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

Atomistic-scale evaluation of the fracture toughness of silicates in aqueous environments

253rd National Meeting (2017)

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