Indentation creep dynamics in metallic glasses under different structural states

Tao, Kaixiang; Khonik, V. A.; Qiao, J.C.

doi:10.1016/j.ijmecsci.2022.107941

Cited by 10 publications

(2 citation statements)

References 76 publications

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“…非晶合金从亚稳态向更稳定能量状态迁移, 玻璃转变温度以下退火导致非晶合金密度增加 [47] 、焓以及缺陷浓度降低 [48,49] , 研究退火行为有利于建立非晶合金β弛豫与微观结构非均匀性之间的联系.…”

Section: 玻璃形成熔体在冷却过程中其动态弛豫行为unclassified

Probing microstructural heterogeneity of La-based amorphous alloy under versatile mechanical stimuli

Zhang,

Hao,

Zhang

et al. 2024

Acta Phys. Sin.

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The intrinsic structural heterogeneities of amorphous alloys are closely connected to the thermodynamics and dynamical behavior, such as relaxation/crystallization, glass transition and plastic deformation. However, the structural information is submerged into the meta-stable disordered long-range structure, which made it very difficult to explore the structural heterogeneities of amorphous alloys. A mechanical excitation factor is not sufficient to effectively describe the heterogeneity of the microstructure in amorphous alloys, particularly the correlation between structure and dynamics. To explore the essence of the structure in amorphous alloys, it is necessary to consider the different mechanical stimuli. La62Cu12Ni12Al14 amorphous alloy was selected as model system, dynamic mechanical processes were probed by dynamic mechanical analysis (DMA). The contributions of a relaxation and b relaxation processes were described in the framework of the quasi-point defects theory. Based on the quasi-point defect theory, the α-relaxation and β relaxation in the La-based amorphous alloy were separated. Tensile strain rate jump measurements were conducted to study the high temperature rheological behavior of amorphous alloy. The contributions of elasticity, anelasticity as well as plastic deformation during the plastic rheology of amorphous alloy are determined within the framework of quasi-point defects theory. The current work aims to reveal the structural heterogeneities of amorphous alloys under the action of dynamics with various temporal scales. The physical background of the activation, propagation and coalescence of defects in amorphous alloys under different mechanical stimuli were reviewed.

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Section: 玻璃形成熔体在冷却过程中其动态弛豫行为unclassified

Probing microstructural heterogeneity of La-based amorphous alloy under versatile mechanical stimuli

Zhang,

Hao,

Zhang

et al. 2024

Acta Phys. Sin.

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“…The nanoindentation tests were carried out by Anton Paar nanoindentation tester NHT 2 with diamond Berkovich indenter (loading/unloading times of 5 s, and dwelling time of 2 s for grid nanoindentation at indentation load of 3 mN; loading/unloading times of 30 s, and dwelling time of 10 s for nanoindentation under various loads) to investigate the micromechanical properties of BST ceramic. Timedependent mechanical properties of material require application of a constant strain rate during nanoindentation test [72,73], which was not used in the current study, since mechanical properties of brittle ceramics can be assumed to be timeindependent, and a constant loading rate was used without considering the effect of strain rate. Moreover, a constant strain rate condition is more difficult to maintain than a constant loading rate, and the measurement by a constant loading rate is more J u s t A c c e p t e d accurate than that by a constant strain rate [39].…”

Section: J U S T a C C E P T E Dmentioning

confidence: 99%

Micromechanical characterization of microwave dielectric ceramic BaO–Sm ₂O ₃–5TiO ₂ by indentation and scratch methods

Liu¹,

Xu²

2023

Journal of Advanced Ceramics

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Mechanical characterization of dielectric ceramics, which have drawn extensive attention in wireless communication, remains challenging. Micromechanical properties with microstructures of dielectric ceramic BaO-Sm2O3-5TiO2 (BST) were assessed by nanoindentation, microhardness, and microscratch tests under different indenters, along with X-ray diffraction, scanning electron microscopy, and Raman spectroscopy. Accurate determination of elastic modulus (i.e., 260 GPa) and indentation hardness (i.e., J u s t A c c e p t e d 16.2 GPa) of brittle BST ceramic by instrumented indentation technique requires low loads with little indentation-induced damage. Elastic modulus and indentation hardness were analyzed by different methodologies such as energybased and displacement-based approaches, and elastic recovery of Knoop imprint. Consistent values (about 3.1 MPa·m 1/2 ) of fracture toughness of BST ceramic were obtained by different methods such as Vickers indenter-induced cracking method, energy-based nanoindentation approaches, and linear elastic fracture mechanics-based scratch approach with a spherical indenter, demonstrating successful applications of indentation and scratch methods in characterizing fracture properties of brittle solids. The deterioration of elastic modulus or indentation hardness with the increase in indentation load is caused by indentation-induced damage, and can be used to determine fracture toughness of material by energy-based nanoindentation approaches, and the critical void volume fraction is 0.27 (or 0.18) if elastic modulus (or indentation hardness) of the brittle BST ceramic is used. The fracture work at the critical load corresponding to the initial decrease in elastic modulus or indentation hardness can also be used to assess fracture toughness of brittle solids, opening new venues of application of nanoindentation test as a means to characterize fracture toughness of brittle ceramics.

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Small punch test for investigating circumferential creep in cladding tubes

Zhong,

Lai,

Guo

et al. 2024

International Journal of Mechanical Sciences

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Indentation creep dynamics in metallic glasses under different structural states

Cited by 10 publications

References 76 publications

Probing microstructural heterogeneity of La-based amorphous alloy under versatile mechanical stimuli

Probing microstructural heterogeneity of La-based amorphous alloy under versatile mechanical stimuli

Micromechanical characterization of microwave dielectric ceramic BaO–Sm ₂O ₃–5TiO ₂ by indentation and scratch methods

Small punch test for investigating circumferential creep in cladding tubes

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Indentation creep dynamics in metallic glasses under different structural states

Cited by 10 publications

References 76 publications

Probing microstructural heterogeneity of La-based amorphous alloy under versatile mechanical stimuli

Probing microstructural heterogeneity of La-based amorphous alloy under versatile mechanical stimuli

Micromechanical characterization of microwave dielectric ceramic BaO–Sm 2O 3–5TiO 2 by indentation and scratch methods

Small punch test for investigating circumferential creep in cladding tubes

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Micromechanical characterization of microwave dielectric ceramic BaO–Sm ₂O ₃–5TiO ₂ by indentation and scratch methods