Co-Cr-Mo-Ni-Fe alloy, with good high temperature strength, thermal stability, resistance to various forms of wear;

Co-Cr-W-C alloy, high hardness, good red hardness, and erosion resistance; The performance of Co-Cr-Al-Y is similar to that of Ni-Cr-Al-Y alloy, but the temperature is higher.

General cobalt-based super alloy lacks a coherent strengthening phase, while in low temperature strength (only 50-75% of nickel base alloy), but in the higher than 980 degrees when has high strength, good thermal fatigue, thermal corrosion and abrasion resistance, and good weldability. It is suitable for making guide vane and nozzle guide vane of aviation jet engine, industrial gas turbine, naval gas turbine and diesel nozzle.

Carbide strengthening phase. The main carbides in cobalt base superalloy are MC, M23C6 and M6C in casting cobalt base alloy. In some alloys, the fine M23C6 can form eutectic with gamma. MC carbide particles are too large to have a significant effect on dislocation directly, so the strengthening effect on the alloy is not obvious, and the fine dispersed carbide has a good strengthening effect. Carbides (mainly M23C6) located at the grain boundary can prevent grain boundary slip, thus improving the lasting strength. The microstructure of cobalt-based high-temperature alloy ha-31 (x-40) is dispersed and the strengthening phase is (CoCrW)6 c-type carbides.

Topologically dense arrangements such as the sigma phase and Laves, which occur in some cobalt-based alloys, are harmful and cause brittle alloys. Cobalt-based alloys are less likely to be strengthened by intermetallic compounds because Co3 (Ti, Al) and Co3Ta are not stable at high temperatures, but cobalt-based alloys strengthened by intermetallic compounds have also been developed in recent years.

The thermal stability of carbide in cobalt base alloy is better. Temperature rise, carbide agglomeration grow up faster than nickel-based alloy phase grew up in both slower, back in the temperature of the substrate is higher (up to 1100 degrees), so when temperature rises, decreasing the strength of the cobalt base alloy is generally slow.

Cobalt base alloy powder has good resistance to corrosion performance, it is generally believed that the cobalt base alloy is better than that of nickel base alloy, in this respect is cobalt sulfides melting point (such as Co - Co4S3 eutectic, 877 degrees) than nickel sulfide melting point (645 degrees) such as Ni - Ni3S2 eutectic is high, and the diffusion rate of sulfur in cobalt nickel in the middle and lower than. Moreover, since most cobalt-based alloys contain more chromium than nickel-based alloys, alkali metal sulfates (such as Cr2O3 protective layer corroded by Na2SO4) can be formed on the surface of the alloys. However, the oxidation resistance of cobalt-based alloys is usually much lower than that of nickel-based alloys. Early cobalt-based alloys were produced by non-vacuum smelting and casting processes. Later developed alloys, such as mar-m509 alloy, because there are more active elements zirconium, boron, etc., with vacuum smelting and vacuum casting production.

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