Abstract
The microstructural instability during creep and its effect on creep behavior were investigated for a martensitic 9Cr-2W steel. The steel was developed as a low radioactive steel suitable for fusion reactor structure. Creep testing was carried out at 873 K for up to 15,100 ks (4200 hours). The creep curve consisted of transition creep, where creep rate decreased with time, and acceleration creep, where creep rate increased with time. During creep, microstructural instability, such as the recovery of dislocations, the agglomeration of carbides, and the growth of martensite lath subgrains, was observed to occur, which resulted in softening but no hardening. The transition creep was a consequence of the movement and annihilation of excess dislocations, resulting in the decrease in dislocation density and the increase in martensite lath size with time. The acceleration creep was a consequence of a gradual loss of creep strength due to the microstructural instability which occurred from the initial stage of creep.
Similar content being viewed by others
References
R.L. Klueh, D.S. Gelles, M. Okada, and N.H. Packan:Reduced Activation Materials for Fusion Reactors, ASTM STP 1047, ASTM, Philadelphia, PA, 1990, pp. 1–247.
M. Tamura, H. Hayakawa, M. Tanimura, A. Hishinuma, and T. Kondo:J. Nucl. Mater., 1986, vol. 141-143, pp. 1067–73.
K.W. Tupholme, D. Dulieu, and G.J. Butterworth:J. Nucl. Mater., 1988, vol. 155-157, pp. 650–55.
K. Asakura, Y. Yamada, and K. Shibata:Trans. Iron Steel Inst. Jpn., 1990, vol. 30, pp. 937–46.
F. Abe, T. Noda, H. Araki, and S. Nakazawa:J. Nucl. Mater., 1991, vol. 179-181, pp. 663–66.
F. Galofalo:Fundamentals of Creep and Creep-Rupture in Metals, Macmillan, New York, NY, 1965, ch. 2.
R.L. Klueh:Metall. Trans. A, 1978, vol. 9A, pp. 1591–98.
F. Abe, H. Araki, T. Noda, and M. Okada:J. Nucl. Mater., 1988, vol. 155-157, pp. 656–61.
F. Abe, T. Noda, H. Araki, and M. Okada: inReduced Activation Materials for Fusion Reactors, R.L. Klueh, D.S. Gelles, M. Okada, and N.H. Packan, eds., ASTM STP 1047, ASTM, Philadelphia, PA, 1990, pp. 130–39.
F. Abe, H. Araki, and T. Noda:Metall. Trans. A, 1991, vol. 22A, pp. 2225–35.
K. Maruyama and H. Oikawa:Proc. Int. Conf. on Creep (Creep ’86), The Japan Society of Mechanical Engineers, Tokyo, 1986, pp. 337–78.
V.K. Sikorsky, M.G. Cowgill, and B.W. Roberts:Proc. Topical Conf. on Ferritic Alloys for Use in Nuclear Energy Technologies, Snowbird, UT, June 1983, The Metallurgical Society of AIME (1984), New York, NY, pp. 413–23.
R.W. Evans and B. Wilshire:Creep of Metals and Alloys, The Institute of Metals, London, 1985, ch. 3, pp. 69–113.
K.R. Williams and B. Wilshire:Mater. Sci. Eng., 1977, vol. 28, pp. 289–96.
K. Maruyama, C. Harada, and H. Oikawa:Trans. Iron SteelInst. Jpn., 1986, vol. 26, pp. 212–18.
T. Matsuo, T. Kisanuki, R. Tanaka, and S. Komatsu:Tetsu-to-Hagané, 1984, vol. 70, pp. 565–72.
K. Kimura, T. Matsuo, M. Kikuchi, and R. Tanaka:Tetsu-to-Hagané, 1986, vol. 72, pp. 474–81.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Abe, F., Nakazawa, S., Araki, H. et al. The role of microstructural instability on creep behavior of a martensitic 9Cr-2W steel. Metall Trans A 23, 469–477 (1992). https://doi.org/10.1007/BF02801164
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02801164