Study demonstrates aging treatment alters microstructure and reduces mechanical properties in martensitic steel.
The T92 martensitic heat-resistant steelwas studied after aging treatment at650°C. With the time extension of aging treatment, the martensite lath of the tempered martensite remained unchanged. The number of precipitates in the microstructure of martensitic heat-resistant steelwas increased gradually. The carbide Cr 23 C 6 and the carbon nitride MXwere formed within grains and on the grain boundaries. The precipitation strengthening produced by the carbide Cr 23 C 6 and the carbon nitride MX has effectively improved the mechanical properties at high temperature. The laves phases, which precipitated after 1000h of aging treatment, were detrimental to the mechanical properties at high temperature. With the time extension of aging treatment, the tensile strengthand the impact toughness were gradually decreased due to the aggregation and growth of carbide Cr 23 C 6 . The fracture mode of the tensile strengthspecimen was brittle cleavage fracture, and the fracture morphology of the tensile specimen was a relatively flat cleavage plane. The fracture mode of the impact toughness specimen changed from transgranular fracture to intergranular fracture gradually, and the fracture morphology changed from dimples to relatively flat cleavage planes.
No takes yet. Share an insight, caveat, or question.
Lu et al. (2025) studied this question.