Interface bonding mechanism and microstructure evolution in current-induced solid-state welding of Zr–Sn/Zr–Sn–Nb alloy

Abstract

Zr–Sn and Zr–Sn–Nb alloys were joined using current-induced solid-state welding. This process led to significant plastic deformation in Zr alloy, resulting in a robust welded joint. The Cu particles, oxides, and other impurities were scattered at the interface. Two distinct microstructures, basketweave-parallel-plate and basketweave-plate, emerged in the weld's center, attributable to varying thermal cycles. The average grain size in Zr–Sn–Nb alloy was smaller than in Zr–Sn alloy side. During the welding of Zr–Sn–Nb alloy, the majority of β-Nb secondary phases particles (SPPs) dissolved. Conversely, in Zr–Sn alloy, elongated, irregular ZrFe2 SPPs were observed between the α plates. The joint formation was influenced significantly by initial slip, twin-induced plasticity (TWIP), and transformation-induced plasticity (TRIP) mechanisms. The joint's burst force was measured between 8790 and 8890 N, and the fractures occurred at a location distant from the weld.