Strengthening effect of incremental shear deformation on Zr alloy sheets

• Incremental shear deformation improves the strength of Zr alloy sheet greatly.
• Much deformation will reduce the ductility and lead to internal microcracks.
• The shear deformation can transform α and β phase into high intensity ω phase.
• The transformation of β phase is preferential during the shear deformation.

To improve the intensity of Zr alloy sheets, the structural evolution and mechanical properties of 47Zr–45Ti–5Al–3V alloys treated with incremental shear deformation were investigated by X-ray diffraction, microhardness tester, nanoindentation, and uniaxial tensile testing. Results indicate that the strengthening effect of incremental shear deformation is significant. The hardness and friction coefficient of sheet specimens increase with increased deformation degree, but considerable deformation reduces their ductility and produces internal microcracks. Strengthening effect is caused not only by cold deformation strengthening, which leads to increased dislocation density, but also by shear deformation, which can transform the α and β phases in the sheet into a high-intensity ω phase (i.e., dispersion-strengthening effect). In the process of shear deformation, β phase transformation is more preferable because of its softness compared with α phase.

To improve the intensity of Zr alloy sheets, the structural evolution and mechanical properties of 47Zr–45Ti–5Al–3V alloys treated by incremental shear deformation were investigated by x-ray diffraction, microhardness tester, nanoindentation, and uniaxial tensile testing. Results indicate that the strengthening effect of incremental shear deformation is significant. The hardness and friction coefficient of the sheet specimens increase with increasing deformation degree, but considerable deformation will reduce the ductility and lead to internal microcracks. The strengthening effect is not only caused by cold deformation strengthening, which leads to increased dislocation density, but also by shear deformation, which can transform the α and β phases in the sheet into high intensity ω phase (i.e., dispersion strengthening effect). The transformation of the β phase is preferable because of its softness compared with that of the α phase in the process of shear deformation.Figure optionsDownload as PowerPoint slide