Plasticity-induced martensitic transformation during cyclic deformation of AISI 304L stainless steel
1989; Elsevier BV; Volume: 114; Linguagem: Inglês
10.1016/0921-5093(89)90871-x
ISSN1873-4936
AutoresM. Bayerlein, H.‐J. Christ, H. Mughrabi,
Tópico(s)High Temperature Alloys and Creep
ResumoSpecimens of AISI 304L stainless steel were deformed cyclically at room temperature at various plastic strain amplitudes Δϵpl/2. In addition to tests at constant plastic strain amplitudes, incremental step tests were also carried out. The cyclic deformation behaviour was investigated and related to microstructural changes observed by transmission electron microscopy (TEM). At low values of the plastic strain amplitude a saturation state was reached, whereas specimens fatigued at plastic strain amplitudes Δϵpl/2 > 0.3% exhibited, after initial cyclic hardening, an extensive secondary hardening stage which persisted until fracture. The reasons for this behaviour were clarified by TEM observations. Planar dislocation arrays with faults were observed after cycling at Δϵpl/2 = 0.02%. However, martensitic phases were not found. The specimens fatigued at Δϵpl/2 = 0.5% or in the incremental step test (0.02%<Δϵpl2<0.5%) displayed cell structures with a considerably higher number of stacking faults. Moreover, deformation-induced martensitic phases were observed and identified as ϵ- and α′-martensite by electron diffraction pattern analysis.
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