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本文通过高压电子显微镜对不同蠕变伸长量和添加不同微量元素(Ti和Mn)的掺杂钨丝的观察,对掺杂钨丝微观组织结构与高温蠕变性能的关系作了进一步的研究。本试验用钨丝直径约为1.25毫米,钨丝的高温蠕变伸长量选为0.5、1.5、2.0和2.5毫米。经电镜观察表明、掺杂钨丝中钾泡的组态与高温蠕变性能密切相关。高温蠕变伸长了0.5和1.0毫米的钨丝中钾泡平均直径分别为360和450A.而0.5毫米蠕变伸长的钨丝中平均直径达900A,高出一倍多,而且钾泡数量少、分布很不均匀。观察到的最长钾泡列,蠕变伸长≤1毫米的钨丝中可达3.5～5.0μm,而蠕变伸长为2.5毫米的钨丝中则钾泡列短得多,为2.0μm。钾泡的数量和弥散化程度是钨丝高温蠕变性能的决定性因素。弥散的钾泡可阻碍位错运动,既可以强化晶内,也可以强化晶界,它们总是有益的。但粗大的钾泡有益的作用不多,危害却不少,它们对位错和晶界的移动的阻碍作用不大,却容易成为位错发射源、裂纹和蠕变空洞形成源,最后会导致钨丝过早熔断。
In this paper, the different creep elongation and the addition of different trace elements (Ti and Mn) of doped tungsten wire were observed by high pressure electron microscopy, and the relationship between the microstructure and the high temperature creep properties of the doped tungsten wire was further studied . The diameter of the tungsten wire used in this test is about 1.25 mm. The high-temperature creep elongation of the tungsten wire is selected to be 0.5, 1.5, 2.0 and 2.5 mm. Electron microscopy showed that the configuration of K-bubble in the doped tungsten wire is closely related to the creep property under high temperature. High-temperature creep 0.5 and 1.0 mm tungsten filament elongation of the average diameter of 360 and 450A, respectively, and 0.5 mm creep elongation of the average diameter of tungsten wire 900A, more than doubled, and the amount of potassium foam Less, distribution is uneven. The longest Kv-column observed, the tungsten filament with creep elongation ≤ 1 mm up to 3.5-5.0 μm, and the tungsten filament with creep elongation 2.5 mm, the potassium was much shorter at 2.0 μm . The amount of potassium bubbles and the degree of dispersion are the decisive factors in the creep behavior of tungsten at high temperatures. Dispersed potassium bubbles can impede dislocation movement, both can strengthen the grain, but also can strengthen grain boundaries, they are always beneficial. But coarse potassium bubble beneficial role in a lot, but a lot of harm, they dislocation and grain boundary movement impeding little role, but it is easy to become a dislocation emission source, cracks and creep cavity formation source, will eventually lead to Tungsten premature blown.