The Determination of the Stress Field Surrounding a Quasi-Constrained Inclusion in a Chromium-3.5nickel Alloy

A method is proposed for estimating the stress field near a semi constrained inclusion. The volume of the stress-free misfit inclusion was separated into totally restricted and only loosely constrained parts. To achieve this, a fictional notch mirroring the inclusion matrices was introduced, and misfit displacement was applied. An elastic finite element analysis under a planar stress condition was conducted to identify the stress field surrounding a hydride blister in the Cr-3.5Ni pressure tube alloy. By assuming the orientation of hydride platelets in the matrix, the precision of computations was demonstrated. Our findings unveil distinct characteristics in the hydride platelet's axial dimension and orientation, highlighting their resistance to self-reorientation, even in the presence of radial hydrides. The consistent size and spacing of hydride platelets around the blister, despite nearby radial hydrides, emphasize the alloy's unique behavior. This study contributes essential insights into the stress dynamics and microstructural intricacies of hydride blister formation, crucial for ensuring the structural integrity of pressure tubes in nuclear reactors.