LONG-RANGE ORDERING IN THE MATRIX OF COMPLEX NICKEL-CHROMIUM BASED ALLOYS.

Variations in phase compositions, structure and properties are investigated on experimental and commercial nickel-chromium based alloys with additions of tungsten, molybdenum, titanium and aluminium, during long ageing in the range 450-650 degree C. The variations of the physical and mechanical properties are due to the combined processes of decomposition and short- and long-range ordering of the matrix according to the type Ni//2Cr. Despite the relatively modest concentration of chromium, the formation of such a superlattice is possible due to the presence of tungsten and molybdenum which substitute the chromium atoms in the superlattice.