The specific composition and properties of nickel-based alloys! ! ! ! !
Nickel-based alloy refers to a type of alloy that has comprehensive properties such as high strength and certain resistance to oxidation and corrosion at high temperatures of 650 to 1000°C. According to the main properties, they are divided into nickel-based heat-resistant alloys, nickel-based corrosion-resistant alloys, nickel-based wear-resistant alloys, nickel-based precision alloys and nickel-based shape memory alloys.
High-temperature alloys are divided into iron-based high-temperature alloys, nickel-based high-temperature alloys and cobalt-based high-temperature alloys according to different substrates. Among them, nickel-based high-temperature alloys are referred to as nickel-based alloys.
Representative materials of nickel-based alloys are: 1. Incoloy alloy, such as Incoloy800, the main component is; 32Ni-21Cr-Ti, Al; it is a heat-resistant alloy; 2. Inconel alloy, such as Inconel600, the main component is; 73Ni-15Cr-Ti , Al; belongs to heat-resistant alloy; 3. Hastelloy alloy, that is, Hastelloy alloy, such as Hastelloy C-276, the main component is; 56Ni-16Cr-16Mo-4W; belongs to corrosion-resistant alloy; 4. Monel alloy, that is, Monel Alloy, such as Monel 400, the main component is; 65Ni-34Cu; it is a corrosion-resistant alloy;
The main alloying elements are chromium, tungsten, molybdenum, cobalt, aluminum, titanium, boron, zirconium, etc. Among them, Cr, Ai, etc. mainly play the role of antioxidant, and other elements have solid solution strengthening, precipitation strengthening and grain boundary strengthening.
It has high strength and certain resistance to oxidation and corrosion at high temperatures of 650 to 1000°C. Due to its high enough high temperature strength and resistance to oxidation and corrosion, it is often used in the manufacture of aircraft engine blades, rocket engines, nuclear reactors, and energy conversion equipment. High temperature parts.
Development History
Nickel-based high-temperature alloys (hereinafter referred to as nickel-based alloys) were developed in the late 1930s. The United Kingdom first produced the nickel-based alloy Nimonic 75 (Ni-20Cr-0.4Ti) in 1941; in order to improve the creep strength, aluminum was added to develop Nimonic 80 (Ni-20Cr-2.5Ti-1.3Al). The United States in the mid-1940s, the Soviet Union in the late 1940s, and China in the mid-1950s also developed nickel-based alloys. The development of nickel-based alloys includes two aspects: improvement of alloy composition and innovation of production processes. In the early 1950s, the development of vacuum melting technology created conditions for refining nickel-based alloys containing high aluminum and titanium. Most of the early nickel-based alloys were deformed alloys. In the late 1950s, due to the increase in the operating temperature of turbine blades, the alloy was required to have higher high-temperature strength. However, when the strength of the alloy was high, it would be difficult or even impossible to deform. Therefore, investment casting technology was used to develop a series of alloys with good performance. High temperature strength casting alloy. In the mid-1960s, directional crystallization and single crystal superalloys and powder metallurgy superalloys with better properties were developed. In order to meet the needs of ships and industrial gas turbines, a number of high-chromium nickel-based alloys with good hot corrosion resistance and stable structure have been developed since the 1960s. In about 40 years from the early 1940s to the late 1970s, the operating temperature of nickel-based alloys increased from 700°C to 1100°C, with an average increase of about 10°C per year.
Ingredients and properties
Nickel-based superalloys are the most widely used. The main reasons are that firstly, nickel-based alloys can dissolve more alloy elements and maintain better structural stability; secondly, they can form coherent and ordered A3B-type intermetallic compounds γ[Ni3(Al, Ti)] As a strengthening phase, the alloy can be effectively strengthened and obtain higher high-temperature strength than iron-based superalloys and cobalt-based superalloys; thirdly, nickel-based alloys containing chromium have better oxidation and resistance properties than iron-based superalloys. Gas corrosion ability. Nickel-based alloys contain more than ten elements, among which Cr mainly plays an anti-oxidation and anti-corrosion role, and other elements mainly play a strengthening role. According to their strengthening mode, they can be divided into: solid solution strengthening elements, such as tungsten, molybdenum, cobalt, chromium and vanadium; precipitation strengthening elements, such as aluminum, titanium, niobium and tantalum; grain boundary strengthening elements, such as boron, zirconium, Magnesium and rare earth elements, etc.
Nickel-based high-temperature alloys include solid solution-strengthened alloys and precipitation-strengthened alloys according to their strengthening methods.
