Migration of Dislocation Boundaries in a Modified P911 3%Co Heat Resistant Steel during Tempering, Ageing and Creep

Abstract:

Effect of carbide precipitation on pinning force and migration mechanism of boundaries of martensite laths was considered in a 3%Co modified P911. The dimensions of second phase precipitations, martensite laths and dislocation densities were measured by means of transmission electron microscopy. The pinning forces retarding the motion of the lath boundaries, that arise from M(C,N) nanoscale precipitations and M₂₃C₆ particles were evaluated by using different models. The pinning pressure evaluated by taking into account a non-uniform distribution of M₂₃C₆ particles was high enough to stabilize the lath martensite structure during tempering and long term ageing. On the other hand, significant coarsening of martensite laths occurred in neck portions of samples subjected to long-term creep tests. Additional effects from dislocation density and applied stress on the motion of lath boundaries are considered in some details.

• Periodical: Materials Science Forum (Volumes 715-716)
• Pages: 953-958
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.715-716.953
• Online since: April 2012
• Authors: Alla Kipelova, Rustam Kaibyshev, Andrey Belyakov, Dmitri A. Molodov
• Keywords: Coarsening of Microstructure, Dispersed Particles, Driving Pressure, Heat Resistant Steel, Long Term Creep, Pinning, Tempered Martensite

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