Phase Field Simulation of Intragranular Microvoids Evolution Due to Surface Diffusion in Stress Field

doi:10.16356/j.1005-1120.2022.03.003

Transactions of Nanjing University of Aeronautics & Astronautics

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Archive > Volume Issue 3 > 2022(3):280-290. DOI:10.16356/j.1005-1120.2022.03.003 Prev Next

Phase Field Simulation of Intragranular Microvoids Evolution Due to Surface Diffusion in Stress Field

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Abstract:

Based on the bulk free energy density and the degenerate mobility constructed by the quartic double-well potential function， a phase field model is established to simulate the evolution of intragranular microvoids due to surface diffusion in a stress field. The corresponding phase field governing equations are derived. The evolution of elliptical microvoids with different stresses Λ， aspect ratios β and linewidths hˉ is calculated using the mesh adaptation finite element method and the reliability of the procedure is verified. The results show that there exist critical values of the stress Λc， the aspect ratio βc and the linewidth hˉc of intragranular microvoids under equivalent biaxial tensile stress. When Λ≥Λc， β≥βc or hˉ≤hˉc， the elliptical microvoids are instable with an extending crack tip. When Λ<Λc， β<βc or hˉ>hˉc， the elliptical microvoids gradually cylindricalize and remain a stable shape. The instability time decreases with increasing the stress or the aspect ratio， while increases with increasing the linewidth. In addition， for the interconnects containing two elliptical voids not far apart， the stress will promote the merging of the voids.

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The work was supported by the Natural Science Foundation of Jiangsu Province of China （No. BK20141407） and the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.

Clc Number:

TN925