Influence of thermo-mechanical and solution annealing treatments on the flow behaviour of 14Cr-15Ni stainless steel

Thermo-mechanical treatment (TMT) involving cold work and annealing is prevalent in enhancing the mechanical properties of precipitation-strengthened stainless steels. This investigation evaluates the effect of TMT and solution annealing treatment (SAT) on the flow properties of a Ti-added 14Cr-15Ni austenitic stainless steel, which is used as cladding material for fast breeder reactors (FBRs). Comparisons drawn with the solution-annealed (SAT) condition showed that TMT enhances the yield stress more significantly compared to the ultimate tensile strength. Analysis of the work-hardening behaviour suggested that though TMT enhanced the initial work-hardening rate, its microstructure was more susceptible to dynamic recovery. Despite exhibiting lower strength, the SAT process enhanced the ductility at all the investigated test temperatures. Adoption of this TMT process on this material has the potential to enhance the performance of the FBR's cladding.