LAUSR

Abstract The microstructure evolution in the growth of zirconium diboride (ZrB2) rods was directly observed with the help of high resolution-transmission electron microscopy. Key features of layered structure and step contours are proposed to interpret the growth mechanism of the new layer on the surface of ZrB2. Under electron beam irradiation, on the surface of the ZrB2 rod amorphous layer first nucleated and grew into two-dimensional (2D) islands. Then with the continuous migration and rearrangement of atoms, the 2D islands began to interconnect and formed a continuous new layer. The energies that govern migration and diffusion of atoms in new ZrB2 layer comes from a high density of islands, interface defects and the distortion energy caused by atomic mismatches in the initial growth stage of each layer.