Allotropic phase transformation of pure zirconium by high-pressure torsion

作者：Edalati Kaveh^*; Horita Zenji; Yagi Shunsuke; Matsubara Eiichiro

来源：Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2009, 523(1-2): 277-281.

DOI：10.1016/j.msea.2009.07.029

• Zirconium
• High-pressure torsion
• Severe plastic deformation
• Omega phase
• Phase transformation
• Allotropic transformation

Pure Zr is processed by high-pressure torsion (HPT) at pressures in the range of 1-40 GPa. A phase transformation occurs from alpha to omega phase during HPT at pressures above similar to 4 GPa while the total fraction of omega phase increases with straining and saturates to a constant level at higher strain. This phase transformation leads to microstructural refinement, hardness and strength enhancement and ductility reduction. Lattice parameter measurements confirm that c for alpha phase is expanded about 0.6% by the presence of omega phase. The temperature for reverse transformation from omega to alpha phase increases with straining and thus, straining under high pressure increases thermal stability of omega phase. The omega phase obtained by HPT is stable for more than 400 days at room temperature.

• 出版日期2009-10-15