Incommensurately modulated structure zone in α-Zr instigated by the drag force on a grain boundary

Among several microstructural features found in deformed Zircaloy-4 alloy, the formation of incommensurately modulated structure (IMS) has not been studied extensively. In this study, an IMS zone in the α-Zr matrix of forged Zircaloy-4 alloy was investigated by transmission electron microscopy and related techniques. The results revealed a new intensity sequence along the (0112) and (0113) planes, implying that an IMS was formed adjacent to a second phase particle (SPP) located at a grain boundary (GB) in the α-Zr matrix. The GB experienced maximum dragging force parallel to the [0110] direction of the α-Zr matrix, resulting in the formation of the IMS zone in the α-Zr matrix adjacent to the SPP.