Evaluation of creep deformation mechanism of heat resistant steel by stress change test

Hiroyuki Hayakawa, Satoshi Nakashima, Junichi Kusumoto, Daisuke Terada, Fuyuki Yoshida, Hideharu Nakashima

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In order to evaluate creep deformation mechanism of heat resistant steels, stress change tests were conducted during creep tests. In this study, it was confirmed that the dislocation behavior during the creep tests was in viscous manner, because no instantaneous plastic strain was observed at stress increments. Transient behavior was observed after stress changes for all kinds of steel in this work. Mobility of dislocation was evaluated by the observed backward creep behavior after stress reduction. Internal stress was evaluated by the change of creep rate in stress increment, and mobile dislocation density was evaluated with the estimated mobility of dislocation and the change of creep rate in stress increment. It was found that the variation of mobile dislocation density during creep deformation showed the same tendency as the variation of creep rate. Therefore mobile dislocation density is the dominant factor that influences the creep rate variation in creep deformation of heat resistant steels investigated in this work. The mobility of dislocation showed a good correlation with 1/T and it is related with the amount of solute Mo that is a solution strengthening element. Microstructure of crept specimens was observed by TEM to discuss the validation of these results.

Original languageEnglish
Title of host publication2007 Proceedings of the ASME Pressure Vessels and Piping Conference - 8th International Conference on Creep and Fatigue at Elevated Temperatures - CREEP8
Pages533-542
Number of pages10
DOIs
Publication statusPublished - May 19 2008
Event2007 ASME Pressure Vessels and Piping Conference - 8th International Conference on Creep and Fatigue at Elevated Temperatures, PVP-2007/CREEP8 - San Antonio, TX, United States
Duration: Jul 22 2007Jul 26 2007

Publication series

Name2007 Proceedings of the ASME Pressure Vessels and Piping Conference - 8th International Conference on Creep and Fatigue at Elevated Temperatures - CREEP8

Other

Other2007 ASME Pressure Vessels and Piping Conference - 8th International Conference on Creep and Fatigue at Elevated Temperatures, PVP-2007/CREEP8
CountryUnited States
CitySan Antonio, TX
Period7/22/077/26/07

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering

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  • Cite this

    Hayakawa, H., Nakashima, S., Kusumoto, J., Terada, D., Yoshida, F., & Nakashima, H. (2008). Evaluation of creep deformation mechanism of heat resistant steel by stress change test. In 2007 Proceedings of the ASME Pressure Vessels and Piping Conference - 8th International Conference on Creep and Fatigue at Elevated Temperatures - CREEP8 (pp. 533-542). (2007 Proceedings of the ASME Pressure Vessels and Piping Conference - 8th International Conference on Creep and Fatigue at Elevated Temperatures - CREEP8). https://doi.org/10.1115/CREEP2007-26501