Abstract: Tungsten-based alloy material sintered at a high sintering power that may contain additive elements soluble in the nickel and selected from the group constituted, for example, by rhenium, molybdenum, tantalum, niobium, vanadium or a mixture of these, wherein, after sintering in liquid phase at a temperature of around 1500° C., it has: a two-phased ?-? microstructure that is fully densified, has no porosities or has negligible porosities of a low mean grain size (L?) and a contiguity (C??) that is very low with respect to the size of the tungsten crystals, and a dispersion of micro-oxides with no loss of ductility properties.

Abstract: Tungsten-based alloy material sintered at a high sintering power that may contain additive elements soluble in the nickel and selected from the group constituted, for example, by rhenium, molybdenum, tantalum, niobium, vanadium or a mixture of these, wherein, after sintering in liquid phase at a temperature of around 1500° C., it has: a two-phased ?-? microstructure that is fully densified, has no porosities or has negligible porosities of a low mean grain size (L?) and a contiguity (C??) that is very low with respect to the size of the tungsten crystals, and a dispersion of micro-oxides with no loss of ductility properties.

Abstract: The invention relates to a process for the production of a heavy tungsten-nickel-iron alloy with high mechanical characteristics comprising the steps of using powders of each of the elements of a FISHER diameter between 1 and 15 .mu.m, mixing the powders in proportions corresponding to the composition of the desired alloy, compressing the powders in the form of compacted items, sintering the compacted items at a temperature of between 1490 and 1650.degree. C. for 2 to 5 hours, treating the sintered compacted items under vacuum at between 1000.degree. and 1300.degree. C., and subjecting the compacted items after treatment under vacuum to at least three cycles of operation, each cycle comprising a working step followed by a heat treatment.

Abstract: The invention relates to heavy tungsten-nickel-iron alloys with high mechanical characteristics and a specific gravity between 15.6 and 18. The alloys include a tungsten .alpha.-phase in the shape of butterfly wings with dislocation cells of dimensions between 0.1 and 1 .mu.m, and a nickel-iron bonding .gamma.-phase having a mean free path of less than 15 .mu.m and an Ni/Fe ratio greater than or equal to 2.

Abstract: A process for reducing disparities of mechanical properties in tungsten-nickel-iron alloys containing in % by weight 85 to 99% of tunsten, 1 to 10% of iron, the alloys being obtained from tungsten, nickel and iron powders which have the same or different grain diameter, shape and size distribution, which entails simultaneously adding an effective amount of each of cobalt and manganese powders to tungsten powder or to a mixture of tungsten, nickel and iron powders.