Monocrystalline alloy with a nickel base matrix

摘要

Monocrystalline alloy with a nickel base matrix without intentional addition of carbon, of boron or of zirconium, having a composition by weight: Co 0 to 10% - Cr 5 to 7% - Mo 1.5 to 2.5% - W 8.5 to 12.5% - Ta 0 to 6.5% - Al 5 to 7% - Nb 0 to 2% - Ni balance to 100. Furthermore, the summation of the atomic percentages 0.005 0.005 Xo+0.036 Cr+0.052 Mo+0.066 W+0.026 Al+0.116 Nb +0.049 Ta is less than one and the summation of the atomic percentages Ta+W+Mo+Nb lies between 5.9 and 6.3. The alloys having an elevated solidus temperature, in excess of 1325 DEG C., are particularly adapted to monocrystalline casting of the vanes of the turbine inlet nozzle array and having significantly improved properties of strength under conditions of thermal fatigue and oligocyclic fatigue.