1991 Volume 77 Issue 4 Pages 590-597
A method of state analysis for α' phase and carbides in high chromium nickel base austenitic alloy has been established. And then, precipitation behavior of the α' phase and carbides and the effect of α' phase on the property of this alloy were investigated by using this method.
The results obtained are summarized as follows.
(1) The α' phase and carbides are quantitatively extracted by potentiostatic electrolysis in 10%HCl-methanol electrolyte.
(2) Only the α' phase in the above mentioned precipitates is dissolved by (1+5)HCl dissolution treatment. Consequently, the amount and composition of the α' phase and carbides can be determined by analysis of this solution and the residues of this treatment, respectively.
(3) The α' phase was bcc chromium phase replaced by a small amount of Mo, Fe and Ni.
(4) In the case of alloys aged for 3 000 h at various temperature, the precipitation of the α' phase was found at aging temperature from 923 K to 1 073 K.
(5) The creep rupture strength was improved by the uniform precipitation of intragranular α' phase.
