The effect of heat treatment and cyclic loading on nanoindentation behaviour of FeSiB amorphous alloy
The effect of heat treatment and cyclic loading on nanoindentation behaviour of FeSiB amorphous alloy
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DOI：
10.1016/j.matdes.2015.12.136
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发表时间：
2016-02-15
影响因子：
8.4
通讯作者：
Li, S.
中科院分区：
文献类型：
--
作者：
Lashgari, H. R.;Cadogan, J. M.;Li, S.
在这项研究中，我们研究了机械性能的Fe 80. 75 Si 8B 11. 25非晶合金的熔体纺丝通过单步和多步纳米压痕法。单步纳米压痕表明，退火处理增加硬度（约13%）和杨氏模量（约46%），然而，不必要的延长退火时间（500 ℃，3小时）降低硬度（约20%）和杨氏模量（约16%）显着。正电子湮没谱（帕尔斯）显示了间隙缺陷和自由体积两个寿命分量，在远低于玻璃化转变点的温度下进行应力松弛处理后，两者的寿命都有所降低。在非晶态下的多步纳米压痕过程中观察到应变硬化行为，导致硬度略有增加（约5%）;然而，在应力松弛样品中的多步纳米压痕（400 ℃，0.5 h）导致整体应变软化现象，并且循环次数（从3到10）的任何增加都不会改变整体软化行为。原子力显微镜（AFM）的压痕表面的非晶样品揭示了应变局部化后的残余的纳米压痕（导致更多的材料堆积相比，单步压痕），这可能是由于在卸载/再加载过程中的应力和/或相互作用和缠结的剪切带诱导的致密化。(C)2015爱思唯尔有限公司版权所有。
In this study we investigate the mechanical properties of Fe80.75Si8B11.25 amorphous alloys produced by melt spinning by means of single-step and multi-step nanoindentation methods. Single-step nanoindentation showed that annealing treatment increases the hardness (by approximate to 13%) and Young's modulus (by approximate to 46%); however, unnecessary prolonged annealing time (500 degrees C for 3 h) decreases the hardness (by approximate to 20%) and Young's modulus (by approximate to 16%) considerably. Positron annihilation spectroscopy (PALS) showed two lifetime components corresponding to the interstitial defects and free volume, the lifetime of both decreased after stress-relaxation treatment at temperature far below the glass transition point. The strain hardening behaviour was observed during multi-step nanoindentation in amorphous state leading to a slight increase of hardness (approximate to 5%); however, multi-step nano indentation in the stress-relaxed sample (400 degrees C for 0.5 h) resulted in an overall strain-softening phenomenon and any increase in the number of cycles (from 3 to 10) did not alter the global softening behaviour. Atomic force microscopy (AFM) of the indented surface in the amorphous sample revealed the strain localization around the residual indent after multi-step nanoindentation (leading to more material pile-up as compared to single-step indent) that could be due to the densification induced by stress and/or interaction and entanglement of the shear bands during unloading/reloading process. (C) 2015 Elsevier Ltd. All rights reserved.