Effect of carbon on microstructure and mechanical properties of DD99 single crystal superalloy
(1.辽宁省沈阳市科学院金属研究所
2.Institute of Metal Research, The Chinese Academy of Sciences, Shenyang 110016, China
3.Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China)
2.Institute of Metal Research, The Chinese Academy of Sciences, Shenyang 110016, China
3.Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China)
Abstract: The effects of carbon on the microstructure and mechanical properties of DD99 single crystal superalloy were investigated. The results show that stress rupture life of DD99 alloy possesses peak value at carbon content of 0.03%(mass fraction). As carbon addition is greater than 0.03%, the stress-rupture life decreases with the increase of carbon content. The tensile strength and yield strength of DD99 alloy reach peak value at 0.08% carbon and 760 ℃. On the contrary, the tensile strength and yield strength have minimal values at 0.08% carbon and 900 ℃. The tensile ductility of DD99 alloy basically decreases with the increase of carbon content at 760 ℃ or 900 ℃. The amount of carbides greatly increases with the addition of carbon content. Dislocation moving is retarded by carbides so that dislocation networks are apt to form, which has an important role on the mechanical properties in DD99 single crystal superalloy.
Key words: single crystal superalloy; microstructure; carbon; mechanical property