Low rhenium and nickel-based single crystal high-temperature alloy and preparation method thereof

Abstract

The invention discloses low rhenium and nickel-based single crystal high-temperature alloy and a preparation method thereof. The alloy comprises the following raw materials by mass percent: 6.75-7.25% of Cr, 7.25-7.75% of Co, 1.3-1.7% of Mo, 5.8-6.2% of W, 5.8-6.2% of Ta, 0.85-1.15% of Re, 5.9-6.1% of Al, 1.3-1.7% of Ti, 0.12-0.18% of Hf, 0.04-0.06% of C, 0.003-0.005% of B, 0.010-0.020% of Y, and the balance of nickel. The method comprises the following preparation steps: smelting master alloy by using a vacuum induction furnace; preparing a master alloy rod by gravity casting; preparing a single-crystal test rod by adopting a seed crystal method through a Bridgeman directional solidification technology; carrying out thermal treatment on single crystal high-temperature alloy. The alloy disclosed by the invention is high in incipient melting temperature, wide in melting temperature range, small in solidification interval, low in alloy density, high in strength, good in oxidation resistance, good in phase stability and low in cost; a harmful phase is not easy to generate in long-term aging.

Description

technical field [0001] The invention relates to a nickel-based single-crystal superalloy and its preparation technology, and in particular provides a low-rhenium, high-performance nickel-based single-crystal superalloy and its preparation method, belonging to the field of superalloy preparation. Background technique [0002] At present, the inlet temperature of aero-engines has reached as high as 1400 °C. The traditional iron-based and cobalt-based superalloys can no longer meet the requirements. There is an urgent need to use alloys with higher temperature-bearing capabilities as turbine blade materials. Nickel-based single crystal superalloys have excellent high-temperature creep and fatigue resistance, as well as excellent oxidation and corrosion resistance, and have become the main material for turbine blades. In the past 30 years of the development of nickel-based superalloys, five generations of nickel-based single crystal superalloys have been developed. The continuo...

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Problems solved by technology

[0003] At present, the second-generation nickel-based single crystal superalloys (such as René N5, PWA1484, CMSX-4, etc.) are widely used at home and abroad. One of the second-generation single crystal alloys, especially nickel-based single crystal superalloys containing rhenium The key problem is that the precipitation of TCP phase (such as σ, μ or p phase) is strongly promoted at high temperature, which drastically deteriorates the performance of nickel-based single crystal superalloys

In addition, it is estimated that after adding 3.0wt% Re to the second-generation rhenium-containing nickel-based single crystal superalloy, the cost of the alloy increases by about 70%, which greatly reduces the market competitiveness of the product.

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