Analysis of meso-scale damage and crack for CuW alloys induced by thermal shock

Considering the mismatch of coefficient of thermal expansion (CTE) of Cu and W phase and temperature gradient, internal and external thermal load are applied on meso-scale 2D representative volume element (RVE) of CuW alloys under thermal shock, respectively. Void volume fraction (VVF) and VVF induced crack are determined by finite element method (FEM) utilizing Gurson–Tvergaard–Needleman (GTN) model, and the driving forces for damage nucleation and growth are analyzed with normal and shear stress as well. The simulation results show that damage and damage induced crack initiate from the vertex of W grain and grow along W/Cu interface, then propagate into Cu phase. After thermal shock experiment on CuW specimen by high voltage arc, micro cracks present along W/Cu interfaces and inside Cu phase, which is in good agreement with simulation results.

► Thermal load induced by temperature gradient play a major role for damage. ► Damage mechanism and damage induced crack behavior are revealed. ► Driving forces for damage are analyzed with shear and normal stress. ► The simulation results are in good agreement with experimental study.