Zr-4合金板材耐疖状腐蚀性能不均匀的问题

Uneven nodular corrosion resistance of Zr-4 alloy

某些批次工业生产的Zr-4合金板材表面上出现了数毫米宽、数十毫米长的光亮程度不同的明亮条纹.利用静态高压釜腐蚀实验、微区成分分析以及织构测定等方法,研究了出现明亮条纹的原因及其对合金材料耐腐蚀性能的影响.实验结果表明:明亮条纹区中Fe和Cr合金元素的含量略高于其周边区域,并且(0001)织构取向因子(fN)也较大;在500℃过热蒸汽中腐蚀3 h后,明亮条纹区的耐疖状腐蚀性能明显优于其周边区域.分析认为,这种明亮条纹以及耐疖状腐蚀性能不均匀的现象是由于Fe,Cr合金元素分布不均匀以及织构取向因子存在差别引起的,而铸锭成分的不均匀是其产生的根本原因.

Some bright stripes with several millimeters in width and several tens of millimeters in length appeared on the surface of Zr-4 plates in certain batches of the products. Autoclave corrosion tests, composition analysis by energy dispersive spectrometer （EDS）, and texture measurement were used to investigate the essentials of bright stripes and their effect on the nodular corrosion resistance. The results showed that the contents of Fe and Cr alloying elements were somewhat higher, and （0001） texture factor （fN） is larger in bright stripe area than that in the surrounding area. Nodular corrosion resistance on the bright stripe area was much better than the surrounding area after corrosion test at 500℃/10.3 MPa in superheated steam after 3 h exposure. The uneven distribution of Fe and Cr alloying elements and the difference of texture factor between the bright stripes and their surrounding area were contributed to the different nodular corrosion resistance. The uneven component of the ingot was the main reason.