氢对N36锆合金包壳管环向拉伸性能的影响

Effect of Hydrogen on Ring Tensile Properties of N36 Zirconium Alloy Cladding Tubes

核反应堆运行期间燃料元件锆合金包壳发生腐蚀吸氢至延性降低,包壳延性降低的程度与吸收的氢含量有必然的联系。采用气相渗氢方法,获得了氢含量在100~1000μg/g范围的试样,开展了不同氢含量对N36锆合金管环向拉伸性能的影响研究。结果表明,当氢含量高于约150μg/g时,延伸率随着氢含量的增加而降低,当氢含量达到1000μg/g左右,延伸率降低到9%左右,仍保留有一定的延性;1000μg/g范围内的氢含量对N36锆合金包壳管拉伸强度和屈服强度的影响都很小。吸氢后N36锆合金包壳管环向拉伸的断裂模式与氢含量有直接的关系,随着氢含量的增加,断口形式表现为从45°剪切断裂到杯锥状断裂再到正向断裂的特征。

Zirconium alloy fuel cladding picks up hydrogen during operation through a corrosion reaction with coolant water,which reduces the ductility of the cladding.However,there is a connection between the extent of hydride embrittlement and hydrogen concentration.The effect of hydrides formed by the gas hydrogen charging method with hydrogen content between 0-1000 μg/g on the ring tensile properties of N36 zirconium alloy cladding tubes was investigated.Results show that the ductility declines with the increasing of hydrogen concentration when exceeding 150 μg/g hydrogen content level.The ductility decreases to 9% when the hydrogen content is about 1000 μg/g.But the hydrogen concentration within 1000 μg/g has little effect on the tensile strength and yield strength.The fracture pattern is found to depend strongly on the hydrogen concentration.With the increase of hydrogen,the fracture types change from 45o shear type fracture to cup and cone type fracture to chisel edge type fracture.