EBSD studies on microstructure and crystallographic orientation of δ-hydrides in Zircaloy-4, Zr-1% Nb and Zr-2.5% Nb

► Hydrides structure and orientation have been analyzed in finished Zircaloy-4, Zr-2.5Nb and Zr-1Nb. ► New crystallographic orientation relationship of (0 0 0 1)α-Zr//{1 0 0} δ-ZrH1.5 was found in Zr-1Nb (E110) alloy. ► The heavy {101¯2} 101¯1¯ tensile twins and {101¯1} 101¯2 compression twins in Zr-1Nb (E110) are responsible for change in crystallographic relation of hydrides in Zr-1Nb (E110) alloy.