RU2588949C1 - ALLOY BASED ON INTERMETALLIC COMPOUND Ni3Al AND ARTICLE MADE THEREFROM - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to cast heat-resistant alloys based on intermetallic compound Ni₃Al, meant for making by directed crystallization and mono-crystal casting hot section parts of gas turbine engines of aviation industry. Alloy based on intermetallic compound Ni₃Al contains, wt%: aluminium 8.2-8.7; chromium 2.5-6.0; molybdenum 2.8-4.2; tungsten 2.8-4.5; titanium 0.01-1.2; tantalum 0.5-5.5; rhenium 0.01-1.4; cobalt 0.01-5.5; carbon 0.015-0.08; lanthanum 0.015-0.4; hafnium 0.01-0.6; zirconium 0.01-0.08; yttrium 0.015-0.15; erbium, neodymium and praseodymium in total content of 0.1-0.3; nickel - the rest.

EFFECT: higher reliability, longer life due to increased heat resistance, short-term strength ( $${\sigma }_W^{20}$$

) and yield strength ( $${\sigma }_{\mathrm{0,2}}^{20}$$

) at room temperature for KGO [001] of an alloy.

2 cl, 2 tbl, 8 ex

Description

The invention relates to the field of metallurgy, and in particular to heat-resistant foundry alloys based on Ni ₃ Al intermetallic, intended for the manufacture by directional crystallization and single-crystal casting, for example, nozzle and working blades, nozzle blade blocks, segments of the combustion chamber, wings and other parts of the hot duct gas turbine engines of the aviation industry.

Known alloy (patent US 6106640, IPC C22C 19/05, C22C 019/05; publ. 08/22/2000) based on intermetallic Ni ₃ Al with the following chemical composition, atomic. %:

Aluminum 10.0-15.5 Chromium 4.0-8.0 Molybdenum 3,5-5,5 Zirconium 0.04-0.2 Boron 0.04-1.5 Nickel rest

The alloy has insufficient tensile strength at elevated temperatures. At a temperature of 1200 ° C, the tensile strength is 130 MPa, the creep strength is 127 MPa. Due to the low strength characteristics, the range of products from this alloy is limited.

Known alloy (patent of the Russian Federation 2198233, IPC С22С 19/05, publ. 02/10/2003) based on intermetallic Ni ₃ Al, the following chemical composition, mass. %:

Aluminum 7.8-9.0 Chromium 5.0-6.5 Molybdenum 3.0-4.0 Tungsten 2.7-4.0 Titanium 0.8-1.2 Carbon 0.001-0.005 Tin 0.03-0.05 Zirconium 0.05-0.5 Nickel rest

as well as a product made of this alloy. The alloy has insufficient heat resistance at a temperature of 1200 s based on a test of 100 hours for crystallographic orientation (CTO) [001], which significantly narrows the scope of applications of products from this alloy.

Known alloy (RF patent 2256716, IPC C22C 19/05, publ. 07/20/2005) based on intermetallic Ni ₃ Al, the following chemical composition, mass. %:

Aluminum 7.7-8.7 Chromium 5.0-6.0 Molybdenum 4,5-5,5 Tungsten 2.5-3.5 Titanium 0.3-0.8 Rhenium 1.2-1.8 Cobalt 4.0-6.0 Carbon 0.001-0.02 Lanthanum 0.002-0.2 Zirconium 0.05-0.5 Nickel rest

as well as a product made of this alloy.

The alloy has insufficient short-term strength and yield strength at room temperature, low heat resistance at temperatures above 1100 ° C, which significantly narrows the scope of applications of this alloy.

A known alloy (RF patent 2484167, IPC С22С 19/05, publ. 06/10/2013) based on intermetallic Ni ₃ Al, the following chemical composition, mass. %:

Aluminum 8.0-8.8 Chromium 3.0-4.0 Molybdenum 4.0-5.0 Tungsten 2.0-3.0 Carbon 0.002-0.05 Cobalt 4.0-6.0 Rhenium 0.15-0.65 Lanthanum 0.005-0.25 Tantalum 5.6-6.4 Cerium 0.001-0.02 Nickel rest

as well as a product made of this alloy.

The alloy has insufficient short-term strength and yield strength at room temperature.

The closest analogue, taken as a prototype (RF patent 2434068, IPC С22С 19/05, published on November 20, 2011), is an alloy based on intermetallic Ni ₃ Al having a chemical composition, mass. %:

Aluminum 8.2-8.7 Chromium 2.5-6.0 Molybdenum 2.8-4.2 Tungsten 2.8-4.5 Titanium 0.01-1.2 Tantalum 0.5-5.5 Rhenium 0.01-1.4 Cobalt 0.01-5.5 Carbon 0.015-0.08 Lanthanum 0.015-0.4 Hafnium 0.01-0.6 Zirconium 0.01-0.08 Yttrium 0.015-0.15 Nickel rest

as well as a product made of this alloy.

) и предела текучести ( $${\sigma }_{\mathrm{0,2}}^{20}$$

) при комнатной температуре для КГО [001] составляют 950 МПа и 700 МПа соответственно, что является недостаточным уровнем для обеспечения требуемой надежности и ресурса работы деталей ГТД.Short-term strength values ( $${\sigma }_{\mathrm{at}}^{\mathrm{twenty}}$$

) and yield strength ( $${\sigma }_{0.2}^{\mathrm{twenty}}$$

) at room temperature for KGO [001] are 950 MPa and 700 MPa, respectively, which is an insufficient level to ensure the required reliability and service life of gas turbine engine parts.

The technical task and the technical result of the invention are to increase the heat resistance at a temperature of 1200 ° C on the basis of 100 hours, short-term strength and yield strength at room temperature for KGO [001] alloy based on intermetallic Ni ₃ Al and products made from this alloy.

To achieve the technical result, we propose an alloy based on intermetallic Ni ₃ Al containing aluminum, chromium, molybdenum, tungsten, titanium, tantalum, rhenium, cobalt, carbon, lanthanum, hafnium, zirconium, yttrium, nickel, which additionally contains neodymium, erbium, praseodymium in the following ratio of components, mass. %:

Aluminum 8.2-8.7 Chromium 2.5-6.0 Molybdenum 2.8-4.2 Tungsten 2.8-4.5 Titanium 0.01-1.2 Tantalum 0.5-5.5 Rhenium 0.01-1.4 Cobalt 0.01-5.5 Carbon 0.015-0.08 Lanthanum 0.015-0.4 Hafnium 0.01-0.6 Zirconium 0.01-0.08 Yttrium 0.015-0.15 Total content Erbium, Neodymium and Praseodymium 0.1-0.3 Nickel rest

and an article made of this alloy.

It has been found that when administered in the proposed alloy based on intermetallic compound Ni ₃ Al, the rare earth metal neodymium, praseodymium and erbium in the claimed ratio of oxygen binding observed in the compound (Nd, Pr, Er) ₂ O _3, difficulty dislocation slip, through the formation of Cotrell atmospheres, hardening of a γ-solid alloy solution and the formation of finely dispersed intermetallic phases like Er ₂ Al ₃ , (Nd, Pr, Er) Al, ErRe ₂ , (Nd, Pr, Er) Ni ₅ , (Nd, Pr, Er) ZrAl ₂ , which leads to a decrease in segregation heterogeneity, an increase in heat resistance at a temperature of 1200 ° C at the base of 100 h aces, increase the short-term strength and yield strength at room temperature for KGO [001], as well as to increase the heat resistance of the alloy at a temperature of 1200 ° C.

) и предела текучести ( $${\sigma }_{\mathrm{0,2}}^{20}$$

) при комнатной температуре для КГО [001] сплава.The use of the proposed alloy based on intermetallic Ni ₃ Al and products made from this alloy leads to an increase in the reliability of products, such as working and nozzle blades, and increases the resource of their work by increasing heat resistance, short-term strength ( $${\sigma }_{\mathrm{at}}^{\mathrm{twenty}}$$

) and yield strength ( $${\sigma }_{0.2}^{\mathrm{twenty}}$$

) at room temperature for the KGO [001] alloy.

Examples of carrying out the invention

The charge stock from the proposed alloy of various compositions and the prototype alloy was smelted from pure charge materials in a vacuum induction furnace with a crucible from the main lining. After casting the alloys into steel pipes with a diameter of 90 mm, chips were taken for chemical analysis. The results of a chemical analysis of the compositions of the proposed alloy and prototype alloy are shown in table 1.

The content of alloying elements, gases, and impurities, such as sulfur, phosphorus, antimony, bismuth, was determined by standard methods.

Then, the melted alloys were remelted in a vacuum setup for high-gradient directional crystallization to obtain billets with a single-crystal structure, the main axis of symmetry of which coincided with the crystallographic growth direction [001], in the form of castings (diameter 16 mm, length 185 mm). Samples for mechanical tensile tests and long-term strength, as well as samples for heat resistance tests, were made from the obtained single-crystal castings.

The mechanical properties of the proposed alloy with a different ratio of components and the prototype alloy were determined on standard samples with KGO [001] at a ratio l / d = 5 according to GOST 1497, GOST 9651, GOST 10145. The criterion is the average of 10 samples per point with a confidence probability 0.8.

The heat resistance tests of the proposed alloy with a different ratio of components and prototype alloy were carried out in accordance with GOST 6130.

The mechanical properties and corrosion resistance of the proposed alloy with a different ratio of components and the prototype alloy obtained by the same technological scheme are shown in table 2.

- на 30-55%, предел прочности ( $${\sigma }_{в}^{20}$$

) - на 2-5%, предел прочности ( $${\sigma }_{в}^{1200}$$

) - на 3-6%, жаростойкость по привесу за 100 часов при температуре 1200°C - на 75-90%.From table 2 it is seen that the properties of the proposed alloy based on intermetallic Ni ₃ Al are higher than the properties of the prototype alloy: time to failure at a temperature of 1200 ° C at a voltage $${\sigma }^{1200}=45\text{MPa}\left({\tau }_{\text{R}}^{\text{1200}}\right)$$

- 30-55%, ultimate strength ( $${\sigma }_{\mathrm{at}}^{\mathrm{twenty}}$$

) - by 2-5%, ultimate strength ( $${\sigma }_{\mathrm{at}}^{1200}$$

) - by 3-6%, heat resistance by weight gain in 100 hours at a temperature of 1200 ° C - by 75-90%.

Claims (2)

1. An alloy based on intermetallic Ni ₃ Al containing aluminum, chromium, molybdenum, tungsten, titanium, tantalum, rhenium, cobalt, carbon, lanthanum, hafnium, zirconium, yttrium, nickel, characterized in that it additionally contains neodymium, erbium and praseodymium in the following ratio of components, in wt. %:
Aluminum 8.2-8.7 Chromium 2.5-6.0 Molybdenum 2.8-4.2 Tungsten 2.8-4.5 Titanium 0.01-1.2 Tantalum 0.5-5.5 Rhenium 0.01-1.4 Cobalt 0.01-5.5 Carbon 0.015-0.08 Lanthanum 0.015-0.4 Hafnium 0.01-0.6 Zirconium 0.01-0.08 Yttrium 0.015-0.15 Erbium, neodymium and praseodymium in their total content 0.1-0.3 Nickel rest 2. The product is made of an alloy based on intermetallic Ni ₃ Al, characterized in that it is made of an alloy according to claim 1.