Abstract: A refractory austenitic alloy suitable for use at temperatures greater than or equal to 1100° C., comprises the following elements in percent by weight: chromium between 25.0% and 32.0%, nickel between 50.0% and 61.0%, aluminum between 1.0% and 6.0%, niobium between 0.15% and 1.50%, carbon between 0.05 and 0.60%, one or more reactive elements in a total content of 0.060% or less, silicon at 0.30% or less, manganese at 0.30% or less, titanium at 0.40% or less, nitrogen at 0.20% or less, vanadium at 1.0% or less, iron between 4.0% and 18.0%, for balancing the elements of the alloy, zirconium, tungsten and sulfur being absent from the alloy, or in the form of impurities. The alloy also satisfies two criteria connecting the percentages by weight of at least some of the elements of the alloy.

Abstract: An austenitic alloy based on nickel and having a high chromium content, intended to be used at a given operating temperature between 900° C. and 1150° C., comprises the following elements by mass percentage: chromium between 40% and 45%; iron between 10% and 14%; carbon between 0.4% and 0.6%; titanium between 0.05% and 0.2%; niobium between 0.5% and 1.5%; at least one reactive element, selected from rare earths or hafnium, between 0.002% and 0.1%; silicon between 0% and 1%; manganese between 0% and 0.5%; nickel to balance the alloy elements. In addition, the alloy has a molar fraction of more than 0.1% of secondary carbo-nitrides rich in niobium and/or titanium, after the operating temperature has been applied thereto. The disclosure also relates to a method for designing such an alloy and to a method for validating such an alloy.

Abstract: An austenitic alloy based on nickel, chromium and iron, and having a high aluminum content, intended for use at a given operating temperature (Ts) between 900° C. and 1200° C., the alloy comprising the following elements, in weight percent: chromium between 20% and 32%, nickel between 30% and 60%, aluminum between 3.5% and 6%, carbon between 0.4% and 0.7%, titanium between 0.05% and 0.3%, niobium and/or tantalum between 0.6% and 2%, an element, composed of at least one rare earth and/or hafnium, between 0.002% and 0.1%, silicon between 0 and 0.5%, manganese between 0 and 0.5%, tungsten between 0 and 2%, and iron as the balance of the elements in the alloy. The alloy has less than 1% by volume of an intermetallic B2-NiAl phase and less than 1% by volume of an alpha prime phase rich in chromium, after subjecting the alloy to an operating temperature (Ts).

Abstract: An austenitic alloy based on nickel and having a high chromium content, intended to be used at a given operating temperature between 900° C. and 1150° C., comprises the following elements by mass percentage: chromium between 40% and 45%; iron between 10% and 14%; carbon between 0.4% and 0.6%; titanium between 0.05% and 0.2%; niobium between 0.5% and 1.5%; at least one reactive element, selected from rare earths or hafnium, between 0.002% and 0.1%; silicon between 0% and 1%; manganese between 0% and 0.5%; nickel to balance the alloy elements. In addition, the alloy has a molar fraction of more than 0.1% of secondary carbo-nitrides rich in niobium and/or titanium, after the operating temperature has been applied thereto. The disclosure also relates to a method for designing such an alloy and to a method for validating such an alloy.

Abstract: An austenitic alloy based on nickel, chromium and iron, and having a high aluminum content, intended for use at a given operating temperature (Ts) between 900° C. and 1200° C., the alloy comprising the following elements, in weight percent: chromium between 20% and 32%, nickel between 30% and 60%, aluminum between 3.5% and 6%, carbon between 0.4% and 0.7%, titanium between 0.05% and 0.3%, niobium and/or tantalum between 0.6% and 2%, an element, composed of at least one rare earth and/or hafnium, between 0.002% and 0.1%, silicon between 0 and 0.5%, manganese between 0 and 0.5%, tungsten between 0 and 2%, and iron as the balance of the elements in the alloy. The alloy has less than 1% by volume of an intermetallic B2-NiAl phase and less than 1% by volume of an alpha prime phase rich in chromium, after subjecting the alloy to an operating temperature (Ts).