Color metallography of U3Si

The physical, mechanical and chemical properties of U3Si make it one of the most potentially attractive fuels for nuclear power reactors. Light metallography was found to be one of the main tools for observing the behavior of U3Si during its formation by the peritectoid reaction and also during plastic deformation. Uranium silicon delta phase was obtained by chill casting, followed by a peritectoid reaction (deltizing) at 620C, 720C, 800C and 860C. The microstructure of U3Si consists generally of transformation twins. The twin boundaries are mobile under stress. Light metallography of U3Si was used to investigate: (a) The distribution of additional phases in the U3Si matrix. (b) Existence or non-existence of twins. A technique for etching U3Si at room temperature is presented. The result is selective coloring of crystallographic faces in various directions. This surface preparation phases in U3Si. Typical structure of U3Si alloys after deltizing at different temperatures as well as after cold working are given in color. Previous methods are also reviewed. (Auth.)