Second phase influence on the hot-compression bonding process of Cu-Cr alloy

• Pre-solution treatment was introduced into hot compression bonding method for the first time, successfully producing uniform Cu-Cr alloy samples. • The effect of second phase particle size on bonding mechanism and its relationship with bonding quality were obtained • Through bonding parameter optimization of hot compression bonding, the mechanical properties of the bonding joint reach the same level as the base material. The segregation of trace elements is a central issue in casting large size ingots of precipitation-strengthening alloys. In this study, we introduced a pre-solution treatment into the hot-compression bonding (HCB) method for successfully additive fabricating homogeneous Cu-0.8Cr alloy specimen. The distribution of second phase and its influence on the interfacial bonding was systematically examined. The results indicate that with an optimized solution treatment time of 2 h at 1000 °C, the average size and number of the primary Cr particles near the interface were decreased to 0.58 μm and 79 particles/mm 2 , respectively. Under this condition, the interfacial grain boundary migration during the HCB process was facilitated, and the dynamic recrystallization behavior transformed from continuous dynamic recrystallization to discontinuous dynamic recrystallization. Therefore, the interfacial tensile-shear strength and elongations reached 284.6 MPa and 4.71 mm, with recovery rates of interfacial strength and plasticity at 98.7 % and 100.6 %, respectively. The interfacial properties of HCBed Cu-0.8Cr alloy were very close to the as-cast specimens, indicating that the additive homogeneous specimens could be further applied in forging process as the castings.