12Cr-Mo-V-W鋼の長時間加熱に伴うLaves相の析出挙動

抄録

Studies on 12Cr-Mo-V-W steel for steam turbine blade show that the Fe₂Mo intermetallic compound, so called Laves phase, is precipitated at grain boundaries after long time heating. The composition of the Laves phase in this steel having internal lattice defects is expressed by the formula (Fe₂₅Cr₇)₂(Mo₂₀W₁₂) and is unchanged after long time heating. The M₂₃C₆-Laves phase transformation appeared to occur in situ, and the growth rate for the Laves phase during heating was larger than that for M₂₃C₆. The Laves phase area fraction was directly proportional to the Larson-Miller parameter (P=T(C+logt)×0.001) in the 23-23.5 range.