Zr-Cu-Cr合金的显微组织及腐蚀行为

以结晶锆为基材配制了7种Zr-Cu-Cr合金样品，经归一化加工及600 ℃/5 h退火处理，在不同水化学条件的静态高压釜中对所制得的Zr-Cu-Cr合金样品进行了腐蚀试验，并采用EBSD、SEM和TEM表征合金基体的显微组织，探究Cu和Cr交互作用对锆合金基体显微组织及耐腐蚀性能的影响。结果表明，添加Cu元素可细化合金再结晶晶粒，Cr含量为1.0%（质量分数）时，合金中出现40 μm以上的较大晶粒。Zr-Cu-Cr合金中存在2种第二相：100 nm以上的体心四方的Zr2Cu相和60 nm以下的密排六方的ZrCr₂相。Zr₂Cu相随Cu含量的增加而增多，ZrCr₂相随Cr含量的增加尺寸变化不明显，但数量及分布条带密度增加。在400 ℃/10.3 MPa过热蒸汽中，Zr-0.3Cu-0.2Cr和Zr-0.3Cu-0.5Cr合金耐腐蚀性能较差，其余合金腐蚀100 d后仍没有发生腐蚀转折，耐腐蚀性能较好，Zr-1.0Cr合金耐腐蚀性能最好。在360 ℃/18.6 MPa/0.01 mol/L LiOH水溶液中腐蚀42 d后，合金的耐腐蚀性能都很差，添加Cu元素会降低其耐腐蚀性能。

Microstructure and Corrosion Behavior about Zr-Cu-Cr Alloy

Seven kinds of Zr-Cu-Cr alloy samples were prepared by using crystalline zirconium as the base material, through normalized processing and annealing at 600 ℃/5 h. The corrosion tests were carried out in static autoclave with different water chemistry conditions, and the microstructures of alloys were studied by using EBSD, SEM and TEM to investigate the effects of Cu and Cr interaction on the microstructure and corrosion resistance of zirconium alloys. The results show that the addition of Cu element refines the recrystallized grains. When the Cr content is 1.0%, it has grains with a size of 40 μm or more. There are two kinds of second phases in Zr-Cu-Cr alloys. Zr₂Cu phase (bct) with a size of 100 nm or more and ZrCr₂ phase (hcp) with a size of 60 nm or less. As the content of Cu increases, the number of Zr₂Cu increases. As the content of Cr increases, the size of ZrCr₂ phase does not change obviously, but the number and distribution band density increase. When exposed to the superheated steam at 400 ℃/10.3 MPa, the corrosion resistance of Zr-0.3Cu-0.2Cr and Zr-0.3Cu-0.5Cr alloys is worse, the other alloys still don’t have corrosion transition after corroding 100 days, and the corrosion resistance is better. Zr-1.0Cr alloy has the best corrosion resistance. When exposed to the 360 ℃/18.6 MPa/0.01 mol/L LiOH aqueous solution for 42 days, all of alloys have poor corrosion resistance, and the addition of Cu element reduces their corrosion resistance.