工业纯锆ECAP单道次变形组织与性能研究

Effect of one pass ECAP on Microstructure and Properties of Commercial Purity Zirconium

摘要:

室温下采用常规ECAP模具(通道夹角90°,内圆角20°)成功实现工业纯锆ECAP单道次变形。通过金相显微镜、透射电子显微镜(TEM)、X射线衍射(XRD)及单向拉伸实验等测试方法,研究ECAP变形后工业纯锆的组织与性能。研究结果表明：工业纯锆经过通道夹角为90°模具单道次ECAP 变形后，晶粒显著破碎,屈服强度和抗拉强度分别提高到397 MPa和536 MPa,增幅分别为~43%和~53%；其硬度值也由原始样的1050 MPa提高到了1550 MPa；材料仍保持有较好的延伸率,延伸率为21.2%。TEM结果显示工业纯锆单道次ECAP变形后试样有大量的板条、位错及位错胞存在。XRD结果表明经ECAP变形后,工业纯锆原始的基面织构和锥面织构转变成了柱面织构。

Abstract:

Commercial purity zirconium (CP-Zr) was processed by Equal channel angular pressing(ECAP) at room temperature using a die with an internal angle Φ of 90°and an outer curvature angle Ψ of 20°. Advanced characterization and measurement techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and so on, were used to analyse microstructural evolution of CP-Zr during one pass ECAP at room temperature. The results showed that the grain of CP-Zr processed by one pass ECAP was refined distinctly. The yield strength and ultimate tensile strength were increased to 397 MPa and 536 MPa (rate of increase up to ~43% and ~53%), respectively. The microhardness value was increased to 1550 MPa. The elongation to failure maintained well. The microstructures of processed CP-Zr observed by TEM proved the existence of elongated bands, dislocations and dislocation cells. The results of XRD indicated that the basal texture and pyramidal texture were transformed to prismatic texture.