淬火冷却速率对Zr-4合金显微组织和耐腐蚀性能的影响  

Effect of Quenching Cooling Rate on Microstructure and Corrosion Resistance of Zr-4 Alloy

作　　者：陈雷 苏斌 孙巧艳[1] 朱波 白新房 CHEN Lei;SU Bin;SUN Qiaoyan;ZHU Bo;BAI Xinfang(State Key Laboratory for Mechanical Behavior of Materials,Xi'an Jiaotong University,Xi'an 710049,China;Xi'an Hantang Analytical Testing Co.,Ltd.,Xi'an 710000,China)

机构地区：[1]西安交通大学金属材料强度国家重点实验室,西安710049 [2]西安汉唐分析检测有限公司,西安710000

出　　处：《机械工程材料》2022年第8期94-99,共6页Materials For Mechanical Engineering

基　　金：国家自然科学基金资助项目(51671158,51621036);国家重点基础研究发展计划(973计划)项目(2014CB644003)。

摘　　要：将Zr-4合金加热至1 000℃保温5 min后分别以200,20,2,0.2,0.02℃·s^(-1)的速率冷却到室温,研究淬火冷却速率对合金显微组织以及在360℃/18.6 MPa水中腐蚀行为的影响。结果表明:随着冷却速率由200℃·s^(-1)降至0.02℃·s^(-1),合金中α相板条的平均宽度由1.4μm增加到28.0μm,第二相颗粒平均粒径由38 nm增大到580 nm;当冷却速率为200,20,2℃·s^(-1)时,第二相颗粒主要分布在α相板条晶界处,而当冷却速率为0.2,0.02℃·s^(-1)时,在α相板条晶界和晶内均有分布;当冷却速率由200℃·s^(-1)降到0.2℃·s^(-1)时,第二相颗粒尺寸的增大有助于释放氧化膜中的压应力,提高合金的耐腐蚀性能;当冷却速率为0.02℃·s^(-1)时,第二相颗粒周围萌生大量微裂纹,耐腐蚀性能降低。0.2℃·s^(-1)冷却速率下的耐腐蚀性能最好,氧化膜断口中的ZrO晶粒主要为结构致密的柱状晶。Zr-4 alloy was heated to 1 000 ℃ for 5 min, and then was cooled to room temperature at cooling rate of 200, 20, 2, 0.2, 0.02 ℃·s^(-1). The effects of quenching cooling rates on microstructure and corrosion behavior of the alloy in 360 ℃/18.6 MPa water were studied. The results show that the average width of α phase plate in alloy increased from 1.4 μm to 28.0 μm, and the average particle size of the second phase particles increased from 38 nm to 580 nm with decreasing cooling rate from 200 ℃·s^(-1)to 0.02 ℃·s^(-1). The second phase particles were mainly distributed in grain boundaries of α phase plate at cooling rate of 200, 20, 2 ℃·s^(-1), and were distributed both inside the crystal and grain boundaries at cooling rate of 0.2, 0.02 ℃·s^(-1). When the cooling rate decreased from 200 ℃·s^(-1)to 0.2 ℃·s^(-1), the increase of the second phase particles helped to release the compressive stress in the oxide film and improved the corrosion resistance of the alloy. A number of microcracks initiated around the second phase particles, and the corrosion resistance decreased at the cooling rate of 0.02 ℃·s^(-1). The corrosion resistance was the best at the cooling rate of 0.2 ℃·s^(-1), and the ZrOgrains in the oxide film were mainly columnar crystals with dense structure.

关 键 词：ZR-4合金 冷却速率 显微组织 耐腐蚀性能 氧化膜 

分 类 号：TG172.5[金属学及工艺—金属表面处理]