The influence of microtexture on the formation mechanism of nodules in Zircaloy-4 alloy tube

• 作者: Chengze Liu Fusen Yuan Fuzhou Han Geping Li Hengfei Gu Muhammad Ali Wenbin Guo Yingdong Zhang
• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2020,（12）
• 页码范围: 68-75
• 页数: 8页
• 语种: 英文

摘要

Corrosion resistance of Zircaloy-4 alloy tube in superheated steam at 673 K/10.3 MPa is anisotropic.A part of the surface undergoes uniform corrosion while the other suffers nodular corrosion.Narrow and wide nodules are observed after an exposure period of 3 and 30 days,respectively.A new matrix transformation method is established in order to study the formation mechanism of nodules in the cross-section (CS) of Zircaloy-4 alloy tube using the EBSD technique,while the CS perpendicular to axial direction (AD).The results reveal that the microtexture is a key factor behind the two types of corrosion.Furthermore,the oxide layers grow anisotropically over the corroded surface.A thick oxide layer forms over the nodular corrosion region on the grains with c-axis oriented in the range of 40° around tangential direction (TD),whereas a thin oxide layer over the uniform corrosion region is detected on the grains with c-axis oriented in the range of 68° around TD.In short,the anisotropic growth of oxide layer was caused by the change of microtexture of the Zr-4 alloy tube,and this anisotropic growth of oxide layer contributed to the nodules formation.