Hydrogen embrittlement in single- and poly-crystal niobium
Hydrogen embrittlement in single- and poly-crystal niobium
复制标题
单晶和多晶铌的氢脆
DOI：
10.1007/bf02649738
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
K. Salama
中科院分区：
文献类型：
--
作者：
M. Farahani;F. Attia;K. Salama
在 373 至 78 K 的温度范围内研究了氢对铌的屈服和延展性的影响。对氢含量在 30 至 230 ppm wt 之间的单晶和多晶样品进行了拉伸测试。应变率为 1.7 X 10-4s-1。还通过 SEM 检查了测试样品的断裂表面。在较高的氢浓度下，在单晶和多晶的均匀应变的温度依赖性中观察到两个延展性最大值。这些最大值在温标上的位置随着溶解的氢量的变化而变化。发现单晶中的最大值之一出现在比多晶中更高的温度下。对所得结果的分析表明存在两种不同的机制导致铌与氢的延展性损失。一种机制在脆化开始时起作用，并且对晶界的存在敏感。第二种机制在第二次韧脆转变的温度下占主导地位，并且与氢化物相的沉淀有关。该机制对单晶和多晶都有类似的影响。
The effects of hydrogen on the yielding and the ductility of niobium have been studied in the temperature range between 373 and 78 K. Tensile tests were undertaken on single- and poly-crystal specimens containing hydrogen ranging between 30 and 230 ppm wt. at a strain rate of 1.7 X 10-4s-1. The fracture surfaces of specimens tested were also examined by means of an SEM. At higher hydrogen concentrations, two ductility maxima were observed in the temperature dependence of the uniform strain of both single- and poly-crystals. The positions of these maxima on the temperature scale varied as a function of the amount of hydrogen dissolved. One of the maxima is found to occur at higher temperatures in single crystals than in polycrystals. Analysis of results obtained indicates the presence of two distinct mechanisms responsible for the loss of ductility in noibium with hydrogen. One mechanism is operative at the onset of embrittlement, and is sensitive to the presence of grain boundaries. The second mechanism predominates at temperatures of the second ductile-brittle transition, and is associated with the precipitation of the hydride phase. This mechanism has similar effects on both single and poly-crystals.