A low-rhenium third-generation nickel-based single crystal alloy and its preparation method

Abstract

The invention belongs to the field of nickel-based high-temperature alloy, and particularly relates to low-rhenium third-generation nickel-based single crystal alloy and a preparation method thereof. The alloy is composed of Cr, Co, W, Mo, Re, Ta, Al, Hf and Ni, wherein the content of Re is 3.0%-4.5%, and the alloy is characterized in that the value of Ta / (W+Mo) is controlled to be between 1 to (1-2). The main steps are that a vacuum self-consuming furnace is adopted, and raw materials are prepared into consumable electrodes which are prepared into mother alloy through multiple tests; and then a directional solidification furnace is adopted for preparing single crystal testing bars through a spiral crystal selection method, and finally the single crystal high-temperature alloy testing bars are subjected to heat treatment. The way of adjusting the value of Ta / (W+Mo) is mainly adopted for improving the persistent strength and hot corrosion resistance of the alloy, the alloy is made to meet the requirement for the third-generation nickel-based single crystal high-temperature alloy, the Re content is low, and no TCP phases are precipitated during long-term ageing at 900 DEG C, so that the stability is good.

Description

technical field [0001] The invention belongs to the field of nickel-based superalloys, in particular to a low-rhenium third-generation nickel-based single crystal alloy and a preparation method thereof. Background technique [0002] Nickel-based single crystal superalloys have excellent comprehensive properties such as creep resistance, fatigue resistance, oxidation resistance and corrosion resistance, and are widely used in blade parts of aero-engines and industrial gas turbines; The content of refractory elements Re, Mo, W, Ta, etc. is constantly increasing, especially the element Re plays an important role. Three generations of nickel-based single crystal superalloys. [0003] Due to the progress of heat treatment technology and alloying theory, the design and preparation technology of nickel-based single crystal alloys has become more common. The composition of the nickel-based single crystal alloy designed by the method is as follows (wt%): Cr2-4%, Co11-13%, W5-7%, Mo...

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Problems solved by technology

Although this method reduces the cost of the alloy to a certain extent, the high content of Cr in the alloy tends to make the stability of the alloy poor at high temperatures, and the content of refractory elements (Re+W+Mo+Ta) is only about 14%. , it is difficult to achieve the performance of the third generation alloy

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