Thermal shock behaviors of W/Cu joints with different structures

Abstract

In this paper, three different W/W-Cu joints (W/W-16Cu (joint 1), W/FeCoNiCrCu interlayer/W-16Cu (joint 2), and continuous graded W-Cu (pure W∼W-16 Cu)/W-52Cu (joint 3)), were prepared by tape casting and infiltration using W and graded W skeleton as substrates. Thermal shock tests at temperature of 800 °C-RT were conducted for the W/W-Cu joints. The microstructure and properties evolution, and damage behavior of the joints under thermal shock were studied by experiment combing with finite element modelling. The results show that, after thermal shock, a crack through the interface is found in joint 1. In joint 2, a main crack originates from the edge of the interface (the position of the maximum thermal stress) and extends inward, and some microcracks occur in the W side near the interface in joint 2. But there is no obvious crack in joint 3. Joint 2 has the highest initial shear strength of 287 MPa, and the joint 3 has the highest residual shear strength. After 150 thermal shocks, the shear strength of joint 3 decreases from 268 MPa to 185 MPa, and the strength loss rate is 30.97 %, while the loss rates of joint 1 and joint 2 are more than 70 %.