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在室温(20℃)和高温(450℃)下,使用1 m V-高压透射电子显微镜(TEM)原位观察了V-4Cr-4Ti合金微观组织结构的演化和点缺陷团簇行为。原位电子辐照诱导Ti-C-O析出物发生分解,并引入缺陷团簇。这些缺陷团簇捕获电子辐照引入的点缺陷,随着辐照剂量的增加而单调长大。分析这些缺陷团簇平均尺寸与辐照剂量的依赖关系发现:当辐照剂量高于1 dpa时,缺陷团簇的长大速率小于辐照剂量低于0.5 dpa时的速率,说明V-4Cr-4Ti合金中缺陷团簇的长大速率随着辐照剂量的增加而减小。167℃下,运用电子加速器对V-4Cr-4Ti合金进行了离位电子辐照实验,采用小冲杆实验法(SPT)对电子辐照前后V-4Cr-4Ti合金样品进行了力学性能测试。发现相比于未经电子辐照的钒合金样品,经过电子辐照的钒合金样品开始发生塑性形变的位移减少了0.04 mm,说明经过电子辐照后,合金发生了延性损失,塑性降低。随着电子辐照剂量的增加,钒合金样品的最大断裂载荷和断裂韧性均单调增加。
The microstructure evolution and point-defect behavior of V-4Cr-4Ti alloy were investigated in situ at room temperature (20 ℃) and high temperature (450 ℃) using 1 m V-high pressure transmission electron microscopy (TEM) Ti-C-O precipitates were induced by in-situ electron irradiation to decompose and introduce defect clusters. These defect clusters capture the point defects introduced by electron irradiation and grow monotonically with increasing radiation dose. The analysis of the dependence of the average sizes of these clusters on the dose of irradiation revealed that the growth rate of the defect clusters was less than that of the irradiated dose below 0.5 dpa when the irradiation dose was higher than 1 dpa, The growth rate of defect clusters in 4Ti alloy decreases with the increase of irradiation dose. The ionization of V-4Cr-4Ti alloy was investigated by using an electron accelerator at 167 ℃. The mechanical properties of the V-4Cr-4Ti alloy before and after irradiation were tested by a small punch test (SPT). It is found that the displacement of plastic deformation of electron-irradiated vanadium alloy specimen decreases by 0.04 mm compared with that of non-irradiated vanadium alloy specimen, indicating ductile loss and ductility reduction of the alloy after electron irradiation. With the increase of electron irradiation dose, the maximum breaking load and the fracture toughness of vanadium alloy all increase monotonically.