Science Daily June 14, 2023
Nanostructured metallic materials with abundant high-angle grain boundaries exhibit high strength and good radiation resistance. While the nanoscale grains induce high strength, they also degrade tensile ductility. A team of researchers in the US (Purdue University, Sandia National Laboratory) showed that a gradient nanostructured ferritic steel exhibited simultaneous improvement in yield strength by 36% and uniform elongation by 50% compared to the homogenously structured counterpart. In situ tension studies coupled with electron backscattered diffraction analyses revealed intricate coordinated deformation mechanisms in the gradient structures. The outermost nanolaminate grains sustained a substantial plastic strain via a profound deformation mechanism involving prominent grain reorientation. This synergistic plastic co-deformation process altered the rupture mode in the post-necking regime, thus delaying the onset of fracture. According to the researchers their discovery highlights the intrinsic plasticity of nanolaminate grains and their significance in simultaneous improvement of strength and tensile ductility of structural metallic materials… read more. Open Access TECHNICAL ARTICLEÂ
Microstructure overview of the as-processed G-T91 steel bar. Credit: SCIENCE ADVANCES, 31 May 2023, Vol 9, Issue 22Â