热轧温度对Zr-Sn-Nb合金腐蚀性能的影响

Influence of Hot-Rolled Temperature on Corrosion Resistance of Zr-Sn-Nb Alloy

将Zr-Sn-Nb合金板坯分别进行610,650,700,800℃热轧、冷轧、中间退火及成品退火处理,然后把它们放入高压釜中分别进行360℃/300d,500℃/500h的腐蚀试验,用扫描电镜研究试样的显微组织和第二相粒子的分布与尺寸。结果表明,610,650℃处理的样品与700,800℃处理的样品比较,前者具有较小的腐蚀增重,360℃/300d时,腐蚀增重比后者减少10%以上,说明其有相对较好的腐蚀性能。通过对4种样品组织中的第二相的统计分析发现,610,650℃试样与700,800℃的组织相比,610,650℃试样组织中第二相尺寸小于50nm的较多可占总数的65%以上,且样品中析出的第二相粒子均匀细小,这就是其腐蚀性能相对较好的原因。总体上,随轧制温度的升高小于50nm的第二相粒子的百分含量减少,第二相粒子长大,导致腐蚀性能恶化。

The Zr-Sn-Nb alloy plates were hot rolled at 610,650,700,800 ℃,respectively.The rolled plates were cold rolled and intermediately annealed,final annealing followed by corrosion tests in autoclave at 360 ℃/300 d and 500 ℃/500 h.Scanning electron microscopy（SEM） was conducted to reveal microstructure and the distribution and size of the second phase particle.As a result.The Zr-Sn-Nb alloy plates of hot rolling at 610 and 650 ℃ were compared with the alloy plates of hot rolling at 610 and 650 ℃.The former had less corrosion gain,and reducing over 10%.It indicated that the former had better corrosion resistance.The statistics of the second phase particles in the four specimens showed that,the second phase particle size less than 50 nm was above 65% in the rolled plates at 610 and 650 ℃,while the proportion of the second phase particle size less than 50 nm in the rolled plates at 700 and 800 ℃ was small,in addition fine and homogeneous second phase particles was precipitated.That was the reason that corrosion resistance of the rolled plates for 610,650 ℃ was relatively better.Generally speaking,the percentage of the second phase particles with size less than 50 nm was decreased with raising temperature,and the second phase particles grew up,which cause corrosion resistance getting worse.