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对电解渗氢后的N18锆合金进行了扫描电镜下原位拉伸试验,观察了裂纹在氢化物中的萌发与扩展过程,研究了氢化物对拉伸性能和断裂行为的影响。研究发现,拉伸时试样会发生颈缩,基体断口上存在大量韧窝,呈韧性断裂,使渗氢后的N18锆合金具有一定的塑性。小裂纹在带状氢化物簇中萌发并迅速扩展,但基体对小裂纹的扩展有钝化作用,使小裂纹转化成孔洞。断口表面上,脆性氢化物与基体之间还会形成二次裂纹,其形状和分布与氢化物的形状和分布相似。孔洞与二次裂纹都会使含氢锆合金的塑性降低。
The in-situ tensile test of the N18 zirconium alloy after electrolytic hydrogenation was carried out by scanning electron microscopy. The growth and propagation of the crack in the hydride were observed, and the influence of hydride on the tensile property and fracture behavior was studied. The results show that when the specimen is stretched, neck shrinkage occurs, and a large number of dimples are present on the fracture surface of the matrix, showing ductile fracture, which makes the N18 zirconium alloy with a certain plasticity after hydrogen permeation. Small cracks in the ribbon hydride clusters germination and rapid expansion, but the matrix of small cracks on the role of passivation, the small cracks into holes. Fracture surface, the formation of secondary cracks between the hydrotalcite and the matrix, its shape and distribution and hydride shape and distribution similar. Holes and secondary cracks will reduce the plasticity of hydrogen-containing zirconium alloys.