Joining and characterization of SPTAs/V/CLAM steel joints using SPDB technique with different current directions

Abstract

Joining the dissimilar materials faces great challenge due to their different physical and chemical performances. In this study, the SPTAs/V/CLAM steel joints were produced by the spark plasma diffusion bonding (SPDB) technique. Investigation of the roles of current direction on the atomic diffusion behavior at interfaces by a scanning electron microscopy and an equipped energy dispersive spectrometer. It is found that the thickness of the diffusion layer at the SPTAs/V interface is independent on the current direction. However, there shows a thicker diffusion layer (σ and vanadium carbide phases) at the V/CLAM steel interface when the current flows through from CLAM steel side to SPTAs side. It is owing to the direction of the electron wind force coincides with the diffusion direction of dominated atom (V). The produced SPTAs/V/CLAM steel joints show good shear strength (201±24 MPa) and thermal cycling performance (35 cycles). In addition, a skillful method was proposed to quantify the directional effect of current on the interdiffusion between Fe and V, accounting for 36.7 %. This study provides a practical and theoretical support on joining dissimilar materials by designing current direction using SPDB technique.