Effect of Cr alloying interlayer on the interfacial bond strength of CuW/CuCr integral materials

The effects of Cr alloying interlayer on the microstructure and mechanical properties of the dissimilar CuW/CuCr joints prepared by sintering-infiltration method were studied. The hardness and electrical conductivity of the CuCr alloy side and the tensile strength of the CuW/CuCr integral materials were tested. The interfacial microstructure and fracture morphology of the CuW/CuCr joints were characterized by X-ray diffraction, optical microscopy, scanning electron microscope equipped with energy dispersive spectrometry. The results show that both the electrical conductivity and hardness of the CuCr alloy side of the aged CuW/CuCr joints are higher than those in the solid solution and infiltration condition. With increase of the Cr content, the regions of eutectic phase are expanded gradually on the CuCr alloy side, and the morphology of Cr particles changes from spot shape to rod-like shape. The highest interfacial bond strength can reach up to 446.66 MPa when Cu15 wt%Cr alloy is introduced into the interfacial region between CuW and CuCr alloy. The interfacial fracture morphology presents more cleavage fractures of W particles, and the Cu/W interphase has a good metallurgical bond.