Hydrogenation behavior of Cr-coated laser beam welds of E110 zirconium alloy

The influence of chromium coating on hydrogenation behavior of laser beam welds (LBW) of E110 zirconium alloy was studied at 360–900 °C and hydrogen pressure of 2 bar. The deposition of Cr coating can slow down hydrogen absorption rate of the LBW samples as activation energy for hydrogen absorption (70 kJ/mol) is higher compared to uncoated ones (61 kJ/mol). The growth of hydrides depends on the hydrogenation conditions and original microstructure of welded alloy in different zones. Nanoindentation and three-point bending tests show that hydride precipitations can cause hardening of LBW E110 alloy samples and loss of its plasticity. Some additional aspects of applying Cr coatings for protection of LBW Zr alloy in hydrogen atmosphere are presented.