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

Abstract

• Y 2 O 3 amorphous layer is magnetron sputtered and W/Fe interface is prepared by laser melting deposition. • Non-crystal Y 2 O 3 by magnetron sputtering promotes nucleation and dispersion distribution of FeW phase. • The increase in thickness of Y 2 O 3 layer improve the bonding strength of the interface. In this study, magnetron sputtering Y 2 O 3 layer has been used as the nucleating agent at tungsten/reduced activation 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 fabricated 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 Y 2 O 3 in solidification and nucleation processes of molten pool. The results showed that Y 2 O 3 as the nucleating agent could considerably promote FeW phase nucleation. With the increase in thickness of Y 2 O 3 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 precipitation. It was also proved that the bonding strength of interface increased with the increase of the thickness of magnetron sputtering Y 2 O 3 layer, which relieved the cracking phenomenon in the heterogeneous interface of tungsten/reduced activation steel.