Both Lawrence Livermore and Oak Ridge National Laboratories are working on high entropy alloys, ones in which equal amounts of 5 or more metals are alloyed. It's a new field and these alloys are difficult to create. They are using Arcam machines at ORNL and ORNL has a technology transfer program. It may be that Hitachi is working with ORNL. It could be that the innovation you mention is using EB to create HIA's and there's no patent infringement.
On the other hand, EB welding has been around for a long time and requires a vacuum as air molecules interfere with electron beams. It's not a big step to go from EB welding and computer aided manufacturing to EB additive manufacturing so the question is, is there only one solution to the problem of creating EBAM when starting from the concept of EB welding? Arcam has a powder solution, Sciaky the wire fed (welding rod) solution. It appears there's at least two solutions.
I'm glad I don't have to worry about patents. I went, one time, to the US Patent Office in DC and had a dizzying experience tracking down patents related to a design I had in mind. When is a design different enough to say it qualifies for a patent? I left having decided I'd had a fine time reading patents, that my design was essentially already patented, then had a pint, then got a good night's sleep.
