Austenitic stainless steels are widely used alloys because of their superior mechanical properties [1-4]. In addition to this, they must have certain characteristics at high temperature such as high yield stress, toughness and ductility, as well as low thermal and electrical conductivity, and good weldability. The astenitic structure of most of these alloys is metastable and martensitic transformation from (fcc) γ to (bcc) α' can occur, producing a ferromagnetic phase, depending on the strain level and temperature [5-11]. This martensitic phase is undesirable for pressure vessels, pipes and other structures operated in a pressurized water environment at high temperature. The γ to α' spontaneous martensitic transformation in the stainless steel is well documented [6, 8, 9, 11, 12]. However, the martensitic transformation induced by plastic deformation at high temperature has received les attention. The mechanisms can be different from those involved during spontaneous transformation or by subzero deformation.
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