Exploitation of new materials processing in a mega-gravity field

A strong acceleration field (mega-gravity) can cause the sedimentation of even atoms and is expected to create an unique one-dimensional crystal strain state, i.e. an instability in molecular or crystalline state in multi-component condensed matter. However, materials science research under the mega-gravity field has now remained unexploited, while microgravity has been much used in many fields. We developed a self-consistent theory for sedimentation of atoms in condensed matter, and an ultracentrifuge apparatus to generate an acceleration of over 1 million (1×10⁶)g at high temperature. Recently, we for the first time formed an atomic-scale-graded structure by the sedimentation of atoms, and observed crystal growth in an alloy under a mega-gravity field. It is expected that the availability of mega-gravity may offer us new and powerful options in materials processing in terms of controlling compositions even of isotopes, of forming atomic-scale-graded structure or nonstoichiometric structure, and of controlling the ordering of atoms or molecules.