The Effects of Impurity Content on Plastic Deformation and Microstructure Evolution in Niobium at Temperatures from 1473 K to 1773 K
The Effects of Impurity Content on Plastic Deformation and Microstructure Evolution in Niobium at Temperatures from 1473 K to 1773 K
复制标题
1473 K 至 1773 K 温度下杂质含量对铌塑性变形和微观结构演变的影响
DOI：
10.1007/s11661-022-06726-x
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Taleff, Eric M.
中科院分区：
文献类型：
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作者：
Brady, Emily A.;Taleff, Eric M.
提出了间隙杂质提高铌高温强度的机理。在1473 K至1773 K（1200 °C至1500 °C）的温度范围内，以10− 3和10−4s−1的恒定真应变率对2型铌板材（ASTM B393-18）进行拉伸力学测试。该材料与具有较低间隙杂质水平的1型铌相比。这两种材料的微观结构，其特征在于使用背散射电子成像（BSE）和电子背散射衍射（EBSD）。这两种材料在这些温度下的变形由五次方蠕变和控制强度的亚晶粒的相关发展主导。与1型材料相比，2型铌的较高间隙杂质含量产生：1.在高温下具有更高的强度，2.延迟再结晶; 3.较慢的晶粒生长，4.更不均匀的微观结构，和5.恢复较慢，产生较小的亚晶粒。这些结果来自于2型铌中间隙杂质所预期的精细分散体，其中碳被确定为最重要的间隙元素。2型铌的更细的亚晶粒尺寸通过五次幂蠕变在这些高温下产生比1型铌更高的强度。
A mechanism is established by which interstitial impurity content increases the high-temperature strength of niobium. A Type 2 niobium sheet material (ASTM B393-18) was mechanically tested in tension from 1473 K to 1773 K (1200 °C to 1500 °C) at constant true strain rates of 10−3and 10−4s−1. This material is compared to a Type 1 niobium with lower interstitial impurity levels. The microstructures of both materials are characterized using backscatter electron imaging (BSE) and electron backscatter diffraction (EBSD). The deformation of both materials at these temperatures is dominated by five-power creep and the associated development of subgrains that control strength. Compared to the Type 1 material, the higher interstitial impurity content of the Type 2 niobium produces: 1. higher strength at elevated temperatures, 2. delayed recrystallization, 3. slower grain growth, 4. more inhomogeneous microstructures, and 5. slower recovery that produces smaller subgrains. These result from the fine dispersoids expected from interstitial impurities in the Type 2 niobium, with carbon identified as the most important interstitial element. The finer subgrain size of the Type 2 niobium produces, through five-power creep, a higher strength than the Type 1 niobium at these high temperatures.