When you select Materials tab in main panel, then on right button click is available context menu that contains two new items Export and Import. Import is available always,

export is accessible only if there is a selected material

You can import material whenever you selected the item Available materials in left upper tree. Then there is menu item Import available in File menu. (Currently works in Spiral Die and Flat Die)

You can export material in XML format whenever material is selected in the tree in the left part of program (currently supported in Material database, Spiral Die and Flat Die). Then there is menu item Export available in File menu.
