Although it's not a new element and basically consists of nickel, it is four to five times lighter than titanium thanks to its unique porous construction which is similar to natural materials such as wood: hence the name Metallic Wood.
The study was led by James Pikul, Assistant Professor in the Department of Mechanical Engineering and Applied Mechanics at Penn Engineering. Here is what he had to say about this material:
The reason we call it metallic wood is not just its density, which is about that of wood, but its cellular nature. Cellular materials are porous; if you look at wood grain, that's what you're seeing — parts that are thick and dense and made to hold the structure, and parts that are porous and made to support biological functions, like transport to and from cells.
Our structure is similar. We have areas that are thick and dense with strong metal struts, and areas that are porous with air gaps. We're just operating at the length scales where the strength of struts approaches the theoretical maximum.