Abstract

The nanocrystalline tantalum alloys were investigated in terms of mechanical properties. The materials were obtained by powder metallurgy techniques—mechanical alloying (MA) and hot pressing (pulse plasma sintering mode). Pure powders of niobium, molybdenum, and tungsten were used for tantalum as an additive element in the concentration of 5, 10, 20, and 40 wt %. The analysis of XRD (Williamson–Hall equation) and TEM confirmed a significant reduction of the grain size (5.3–25.7 nm) for pure powders and (12.5–171.5 nm) for bulk hot-pressed elements. The nanoindentation test was used to study the mechanical properties. The load-displacement curves show high uniformity of the mechanical properties. The nanocrystalline alloys show very high hardness and stiffness. The highest value of hardness reached 1481 HV for Ta–10Mo composition. Significantly higher values of hardness compared to pure Ta-nano were measured for Ta–W system. The Young’s modulus increased twice up to 343 GPa for Ta–20Mo in comparison to the unalloyed nanocrystalline Ta (163 GPa). In the novel nanocrystalline tantalum alloys, both solid solution and grain boundary strengthening affected on high mechanical properties.

中文翻译：

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新型纳米晶难熔钽合金的力学性能

摘要

就机械性能研究了纳米晶钽合金。这些材料是通过粉末冶金技术-机械合金化（MA）和热压（脉冲等离子烧结模式）获得的。铌，钼和钨的纯粉末以5、10、20和40 wt％的浓度用于钽作为添加元素。对XRD（Williamson-Hall方程）和TEM的分析证实，纯粉末的晶粒尺寸（5.3-25.7 nm）显着减小，大块热压元件的晶粒尺寸（12.5-171.5 nm）显着减小。纳米压痕测试用于研究机械性能。载荷-位移曲线显示出机械性能的高度均匀性。纳米晶合金显示出非常高的硬度和刚度。Ta-10Mo成分的最高硬度值达到1481 HV。Ta-W系统测得的硬度值比纯Ta-nano高得多。与未合金的纳米晶体Ta（163 GPa）相比，Ta-20Mo的杨氏模量增加了两倍，达到343 GPa。在新型纳米晶钽合金中，固溶体和晶界强化都影响高机械性能。