Excellent high-temperature strength and ductility of the ZrC nanoparticles dispersed molybdenum
Excellent high-temperature strength and ductility of the ZrC nanoparticles dispersed molybdenum
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DOI：
10.1016/j.actamat.2022.117725
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发表时间：
2022-02-17
期刊：
影响因子：
9.4
通讯作者：
Wu, X. B.
中科院分区：
文献类型：
--
作者：
Jing, K.;Liu, R.;Wu, X. B.
界面控制在开发用于空间反应堆等高温应用的高性能钼（Mo）合金中至关重要。本文通过纳米级ZrC的分散和界面控制制备了具有优异室温和高温力学性能的纳米Mo-ZrC合金。Mo-ZrC合金的平均晶粒尺寸仅为0.67 μ m，这是由于纳米ZrC颗粒的均匀分散。室温下，Mo-ZrC合金的抗拉强度和延伸率分别为928 MPa和34.4%。在1000摄氏度下，UTS仍然高达562 MPa，这明显高于氧化物弥散强化Mo合金中报道的那些，而TE仍然保持23.5%的高值。此外，Mo-ZrC合金的再结晶开始温度约为1400 ℃，表明具有显著的热稳定性。第一性原理计算表明，间隙氧降低了晶界的结合力，而C和ZrC由于具有较强的Mo-C键而提高了晶界的断裂强度。Mo-ZrC合金优异的力学性能和热稳定性是纳米ZrC颗粒弥散强化、细晶强化和晶界净化协同作用的结果。该策略可应用于设计具有高强度和高延展性的高温应用的其他耐火合金。(c)2022 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
The interface control is critical in the development of high-performance molybdenum (Mo) alloys for high-temperature applications like space reactors. In this work, nanostructured Mo-ZrC alloy with excellent mechanical properties at both room temperature and high temperatures was fabricated by nanoscale ZrC dispersion and interface control. The average grain size of Mo-ZrC alloy is only 0.67 mu m owing to the homogeneous dispersion of nanoscale ZrC particles. At room temperature, the ultimate tensile strength (UTS) and total elongation (TE) of the Mo-ZrC alloy are 928 MPa and 34.4%, respectively. At 1000 degrees C, the UTS is still as high as 562 MPa, which is significantly higher than those reported in oxide dispersion-strengthened Mo alloys, while the TE remains a high value of 23.5%. Additionally, the recrystallization start temperature of Mo-ZrC alloy is about 1400 degrees C, indicating remarkable thermal stability. First-principles calculations revealed that the interstitial oxygen reduces grain boundary cohesion, while C and ZrC could increase the fracture strength of the boundaries owing to the strong Mo-C bonds. The excellent mechanical properties and thermal stability of the Mo-ZrC alloy can be attributed to a synergistic effect of nanoscale ZrC particles dispersion strengthening, fine-grain strengthening, and grain boundary purification. The strategy could be applied to design other refractory alloys with both high strength and ductility for high-temperature applications. (c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.