Plastic Deformation of Nanocluster-Strengthed Ferritic Steel Studied by In-Situ Neutron Diffraction

• Published in: AIP conference proceedings 2012-03
• Main Authors: Stoica, Alexandru, Stoica, Grigoreta, Zhang, Zhongwu, Wang, Xun-Li
• Format: Article
• Language: English
• Subjects: Dislocation pinning; Ferritic stainless steels; Nanocomposites; Nanomaterials; Nanostructure; Neutron diffraction; Plastic deformation; Steels
• ISSN: 0094-243X

In-situ neutron diffraction data were recorded on nanocluster-strengthed ferritic steel specimens under uniaxial tensile loading. The tensile experiments were performed at RT and 800 degree C in displacement-controlled mode. The RT measurements reveal the evolution of lattice strains and intragranular accumulation of microstrains due to the plastic deformation. Both, the development of intergranular stresses and the increase of residual dislocation densities with the level of stress, prove that RT plasticity in nanocluster-strengthed ferritic steel is mediated by dislocation slip, and the material undergoes a strain hardening by dislocation pinning on nanoclusters. At high temperatures, the deformation process seems to be different. The absence of plasticity-induced intergranular strains, as well as, a modest intragranular broadening, suggest a diffusion-controlled grain-boundary sliding as the main plastic deformation mode at high temperatures. An unusually low creep rate was observed in constant load experiments and diffraction data confirm the outstanding stability of microstructure at high temperature.