5Holt R T, Wallace W. Impurities and trace elements in nick-el-base superalloys[J]. Int. Met. Rev., 1976,21 (5): 1-24.
6Yamaguchi S, Kobayashi H, Matsuiya T. Effects of minor ele- ments on hot workability of nickel-base superalloys [J]. Metals Techno., 1979,6(5): 170-175.
7Hong J H, Nam S W, Choi S P. The influences of sulphur and phosphorus additions on the creep cavitation characteristics in type 304 stainless steels [J]. J. Mater. Sci.,1986,21 (11): 3966-3976.