Le Li , Jun-Ping Du , Shigenobu Ogata , Haruyuki Inui
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引用次数: 0
摘要
通过实验和理论分子动力学(MD)模拟,研究了等原子铬-钴-镍中熵合金(MEA)在纳米压痕中首次弹入载荷随退火温度和时间的变化。通过实验和 MD 模拟,无论加载速率如何,首次弹入载荷都会随着电阻率的增加而增加。弹入载荷随退火温度/时间的变化趋势与我们之前的研究中观察到的电阻率变化趋势相吻合,这表明纳米压痕中的首次弹入载荷可用于定性检测铬-铬-镍 MEA 中短程有序化(SRO)的演化,而等原子铬-铬-镍 MEA 的 SRO 峰值温度为 673 K。MD 模拟表明,在两种退火条件下,首次弹入都与压头下方部分位错环的成核相对应,而纳米压痕中首次弹入载荷的增加是由于 SRO 程度较高导致位错环成核的能量势垒较高所致。
Variation of first pop-in loads in nanoindentation to detect chemical short-range ordering in the equiatomic Cr-Co-Ni medium-entropy alloy
The variations of the first pop-in load in nanoindentation with annealing temperature and time have been investigated both by experiment and theoretical molecular dynamics (MD) simulations for the equiatomic Cr-Co-Ni medium-entropy alloy (MEA). Regardless of the loading rates, the first pop-in load tends to increase with the increase in electrical resistivity consistently by experiment and MD simulations. The trend in the variation of pop-in load with annealing temperature/time coincides with what is observed in the variation of electrical resistivity in our previous study, indicating that the first pop-in load in nanoindentation can thus be used to qualitatively detect the evolution of short-range ordering (SRO) in the Cr-Co-Ni MEA, and that the peak temperature for SRO for the equiatomic Cr-Co-Ni MEA is 673 K. MD simulations indicate that the first pop-in corresponds to the nucleation of partial dislocation loops beneath the indenter for both annealing conditions and that the increased first pop-in load in nanoindentation is attributed to the higher energy barrier for the nucleation of dislocation loops due to the higher degree of SRO.
期刊介绍:
Acta Materialia serves as a platform for publishing full-length, original papers and commissioned overviews that contribute to a profound understanding of the correlation between the processing, structure, and properties of inorganic materials. The journal seeks papers with high impact potential or those that significantly propel the field forward. The scope includes the atomic and molecular arrangements, chemical and electronic structures, and microstructure of materials, focusing on their mechanical or functional behavior across all length scales, including nanostructures.