DD408 (DD8) is a nickel-based precipitation hardening single crystal superalloy, the service temperature is below 1000, the alloy has high creep strength and fatigue resistance, good single crystal casting performance, and has good microstructure stability. The alloy can work in the oxidizing atmosphere and hot corrosion environment for a long time, and its oxidation resistance and hot corrosion resistance are better than those of K438 alloy, and the temperature bearing capacity is 40 higher than that of K438 alloy. It is about 20 higher than DZ438G alloy. It is suitable for the manufacture of turbine blades of coastal aircraft engines and turbine blades of naval gas turbines and other high-temperature components for working below 1000.
The temperature bearing capacity of DD408 (DD8) single crystal superalloy is about 40 higher than that of K438 alloy and about 20 more than that of DZ438G alloy. This means that it can operate at higher temperatures, making it ideal for making turbine blades and other high-temperature components for coastal aircraft engines and off-board gas turbine blades up to 1000 meters. 
Chemical Composition: Sulfur S (0.)010) cobalt co (800~9.00) Tungsten W (5.)60~6.40) Manganese mn (0.).150) silicon si( 0150) Chromium Cr (15.)50~16.50) Fe (0.)50) Phosphorus p(0.)010) nickel Ni (margin) carbon c ( 003) Chromium CR (15.)50~16.50) Zirconium zr ( 0007）