N36锆合金包壳管环向拉伸I-SCC行为评价(英文)

I-SCC Behavior Evaluation of N36 Zirconium Alloy Cladding Using Ring Tensile Test

在102,103,104Pa碘蒸气压力和350℃温度条件下对N36锆合金包壳管进行I-SCC(碘致应力腐蚀)环向拉伸试验。对拉断后的环形试样进行宏观观察。碘环境下的试样表现出脆性断口,不同于无碘环境下的杯-杯形韧性断口形貌。分析试验载荷-位移曲线及力学参数,评价试样的I-SCC敏感性。碘环境下力学性能均较无碘环境下降,且下降程度随着碘浓度的升高而增大。通过对I-SCC评价参数的筛选,采用以拉伸载荷-位移曲线下面积表示的韧性作为I-SCC敏感性评价参数,结果表明包壳管韧性随着碘浓度的增加而降低。

A ring tensile test was performed to study the iodine-induced stress corrosion cracking（I-SCC） behavior of N36 zirconium alloy cladding at 350 °C and in 102, 103, 104 Pa iodine vapor pressures. Morphologies of ring samples were observed by optical microscope, ring tensile load-displacement curves and parameters were analyzed to evaluate I-SCC susceptibility. The fracture surfaces of samples after test show the brittle fracture in iodine vapor which is different from cup-cup ductile fracture with non-iodine. Load-displacement curves and parameters show that the mechanical properties are degraded in iodine vapor environment compared to that in non-iodine environment, and more significantly decrease when increasing iodine content. Cladding tube toughness is considered to be an appropriate parameter to assess the I-SCC susceptibility; as a result, cladding toughness decreases gradually with the increasing of iodine content.