Interfacial reactions between ZrSnNb and FeCrAl alloy during diffusion bonding, hot-rolling and annealing

Abstract

The clad plate between ZrSnNb and FeCrAl alloy was fabricated through diffusion bonding at 850 °C for 5 h under mechanical pressure in an argon atmosphere, and subsequent hot rolling at 800 °C with 20, 37 and 50% rolling reduction. The annealing treatment on hot-rolled plate was carried out in vacuum at 800 °C for 480 h. Interface observation and phase analysis were performed by Electron Probe X-ray Micro-Analyzer (EPMA). The interface of clad plate was tightly bonded, and there were no cracks and pores. After 5 h solid-state diffusion bonding, the Zr3Fe phase formed at the diffusion layer with about ∼3 μm thickness. The αZrCr2, ZrFe2 and Zr3Al intermediate phases formed at the interface in the 20% and 50% hot-rolled samples. While αZrCr2, Zr3Fe and Zr3Al phases formed at the interface in the 37% hot-rolled sample. There is no reasonable evidence temporarily to explain the formation of Zr3Fe phase at diffusion layer of 37% hot-rolled sample, and further study is necessary in near future. After annealing at 800 °C for 480 h, intermetllics formed and identified as αZrCr2, ZrFe2 and Zr3Al and Zr2Fe. The average thickness of diffusion layer in FeCrAl/ZrSnNb clad plates with 20%, 37% and 50% rolling reduction was 6 μm, 9 μm and 11 μm, respectively. The results in this study could provide possible valuable guidance for fabricating multilayer fuel cladding materials for the application in nuclear reactor.