| Abstract Scope |
A Ta-free directionally solidified superalloy, designated DZ409, was recently developed by Central Iron & Steel Research Institute(CISRI) for heavy IGT(Industry Gas Turbine) blades application. Based on the principles of materials design, several alloy compositions were designed with the control of Ti/Al and W/Mo ratio and partial substitute Ta for Nb. The resultant nominal composition of DZ409 alloy contains 0.1C, 15Cr, 9.5Co, 4.5W, 1.5Mo, 3Al, 4.5Ti, 2Nb, 2Ta and bal.Ni in a weight percentage. The alloy exhibits excellent high temperature mechanical properties, oxidation resistance and hot corrosion resistance properties. Under the condition of 75%Na2SO4+25%NaCl cycled coated at 950℃, the mass loss of DZ409 is similar to DS GTD111. After aging at 950℃for 5000h, no TCP phases were observed, indicating that DZ409 alloy possesses a good microstructure stability. |