Optimization mechanism of bonding strength of laser melting deposited tungsten/reduced activation steel heterogeneous interface via addition of Y2O3 by magnetron sputtering

In this study, magnetron sputtering Y2O3 layer has been used as the nucleating agent at tungsten/reduced ac-tivation steel interface for solving the bonding difficulty between tungsten and reduced activation steels owing to the formation of FeW phase and the huge residual stress at tungsten/reduced activation steel interface fab-ricated by laser melting deposition. Moreover, SEM, EBSD and nanoscratch methods were applied to study the interfacial microstructure and mechanical properties of tungsten/reduced activation steel interface for exploring the action mechanism of Y2O3 in solidification and nucleation processes of molten pool. The results showed that Y2O3 as the nucleating agent could considerably promote FeW phase nucleation. With the increase in thickness of Y2O3 layer, mutual diffusion of W and Fe was decreased consequently, making the distribution of precipitated FeW phase more dispersed to effectively inhibit the formation of cracks caused by coarse FeW phase pre-cipitation. It was also proved that the bonding strength of interface increased with the increase of the thickness of magnetron sputtering Y2O3 layer, which relieved the cracking phenomenon in the heterogeneous interface of tungsten/reduced activation steel.