The Reversion of Martensite to Austenite in an Fe–16Cr–12Ni Alloy

Abstract

The isothermal transformation of martensite to austenite has been investigated in an Fe–16Cr–12 wt.-%Ni alloy at various temperatures below A_f , using magnetic measurements and ∼tructural observations. Three stages of transformation were found to occur. The first was athermal in nature and occurred in the range ∼530–600° C (i.e. A _s – A _r). The second stage, observed at 540 and 550° C, was small in magnitude, and may represent austenite formation by an isothermally occurring martensitic mode of transformation. The third stage was detected in the range from∼570° C down to temperatures well below A _s; it involved the transformation of martensite to austenite over a prolonged period, together with the diffusion-controlled formation of ferrite; the formation of this phase occurred more rapidly from deformation-induced martensite than from quench-induced martensite.