Reversible Phase Transformation in Polycrystalline TRIP Steels Induced by Cyclic Indentation Performed at the Nanometric Length Scale. Issue 11 (17th September 2018)

• Record Type: Journal Article
• Authors: Roa, Joan Josep; Sapezanskaia, Ina; Fargas, Gemma; Kouitat, Richard; Redjaïmia, Abdelkrim; Mateo, Antonio Manuel
• Is Part Of: Steel research international. Volume 89:Issue 11(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-09-17
• Subjects: cyclic indentation -- metastable austenitic stainless steels -- nanoindentation -- plastic deformation mechanisms -- reversible phase transformation; Steel -- Periodicals; Steel -- Metallurgy -- Periodicals; 669.142
• DOI: 10.1002/srin.201800234
• Languages: English
• ISSNs: 1611-3683

Abstract

Abstract : Metastable austenitic stainless steels are an interesting group of materials, which exhibit the Transformation Induced Plasticity effect. In this regard, phase transformation from austenite to martensite enhances the work hardening of the metastable austenitic stainless steels affecting the deformation dynamics and mechanical properties including fatigue properties. Within this context, the reversible load‐induced phase transformation from γ to ϵ ‐martensite is investigated at the local scale under cyclic indentation. This reversible phase transformation is manifested itself by a combination of hysteresis loops, elbow formation, and reversible pop‐ins in the loading curve. The initial cyclic achieved through the nanoindentation technique allows to identify three different deformation regimes for the <111> austenitic grains. Firstly, a softening effect takes place due to the dislocation activation; subsequently the phase transformation induces a hardening effect and finally, the load deformation curve reaches a plateau where no more plastic deformation is observed. Abstract : In the present work, reversible phase transformation from austenitic to ϵ ‐martensitic phase in polycrystalline TRIP steels is investigated. Cyclic indentation tests at the nanometric length scale, under loading control mode, are performed in an annealed specimen with a coarse grained structure. Three different deformation regimes appear: dislocations (softening effect), phase transformation (hardening effect), and no more features (plateau).