molybdenum 5 chromium 15 cobalt 17 balance nickel this alloy has a solvus temperature of 1140 u00b0 c a conventional method for obtaining a product based on prealloyed powder in the abovementioned proportions by weight consists of high temperature densification treatment under pressure for example heat treatment under 100 mpa for six hours table a below gives the sizes of the grains obtained in accordance with the astm standard in relation to the temperature of this heat treatment for powder particles having a mean diameter of less than 75 micrometres table a______________________________________ astm standardastroloy treatment s grain sizes______________________________________methods according to 1120 u00b0 c 6 h 100 mpa 10the state of the art 1160 u00b0 c 6 h 100 mpa 7 1200 u00b0 c 6 h 100 mpa 6______________________________________ an example of a method according to the invention consists of the prior heat treatment of powders under low pressure less than 1 atm or without pressure for 24 hours followed by compaction heat treatment in which one stage is a hot isostatic pressing stage at 1160 u00b0 c and 100 mpa for six hours this isostatic pressing stage being possibly followed by treatment for four hours at a temperature of 1200 u00b0 c the grain sizes obtained from initial powders having.