Three-dimensional α-Mg dendritic morphology and branching structure transition in Mg-Zn alloys

• The morphologies of α-Mg dendrites in Mg-Zn alloys were characterized.
• Dendritic morphology transition was found with increasing zinc addition.
• Four kinds of α-Mg dendrite morphology with different zinc contents were revealed.
• Hyperbranch structure was observed with an interim addition of zinc.

Three-dimensional dendritic morphology and branching structure of hexagonal close-packed α-Mg in magnesium-zinc alloys possessing different zinc concentrations were studied using synchrotron X-ray microtomography. Interestingly, dendrite growth patterns were observed to undergo a morphologic transition with increasing zinc addition. Dendrite arms in the basal plane of hexagonal close-packed α-Mg tend to split and deviate from the basal plane continuously and symmetrically as a function of zinc concentrations. A hyperbranched dendrite structure was also found with an interim zinc concentration. Several types of dendrite growth patterns with different morphologies and branching structure were proposed in order to reflect the evolution of α-Mg dendrites with various zinc contents.

Three distinctive dendrite growth patterns observed in Mg-Zn alloys with different zinc addition.Figure optionsDownload as PowerPoint slide