Structure of Internally Nitrided Mo-Zr Alloys.

Internal nitriding, like internal oxidation, is a method of introducing particles of refractory compounds into a metallic matrix. Mo plus 2wt%Zr and Mo plus 0. 2wt%Zr alloys obtained by fusing electron-beam remelted Mo with zirconium iodide in an electric are furnace were investigated. Nitriding took place at 1400, 1600 and 1800 degree C in nitrogen with minute addition of oxygen-containing compounds. It was found that the formation of two zones parallel to the surface of the specimen is due to the simultaneous occurrence of the processes of internal oxidation and internal nitriding. Internal oxidation affects the two-phase alloy, molybdenum-zirconium nitride.