Particulate scale MPFEM modeling on thermal load of W and Cu composite coating

Abstract

In this paper, the thermal loading process of two-dimensional W and Cu composite coating was simulated by multi-particle finite element method (MPFEM) from particulate scale. The initial random structure of the powder particles inside the coating, obtained by discrete element method (DEM), was input into FEM model where the mesh division of each W particle and Cu matrix was discretized. The effects of Cu content and temperature on thermal stress distribution and force transmission in the coating during thermal load were systematically analyzed. The results indicate that with the increase of Cu content, the thermal stress concentration area of the coating decreases under the same temperature, and the force chain structure becomes loose. When the coating with fixed Cu content is exposed to a thermal load at 600 K, the maximum thermal stress between W/Cu phases can reach 200 MPa. With the increase of temperature, the area and value of thermal stress concentration increase gradually. Large thermal stress appears in and around W particles with random loose structure, with a value of about 300 MPa. The internal stress of W particles with random dense arrangement is relatively small, with a value below 200 MPa. At the same time, the average internal stress of W particles is about 150 MPa, and the maximum difference between high and low thermal stresses can reach 230 MPa. The MPFEM model can well predict the thermal stress of composite coatings, which provides a more accurate and effective solution scheme for coating preparation and process optimization.