On dissipative gradient effect in higher-order strain gradient plasticity: the modelling of surface passivation

Hua, Fenfei; Liu, Dabiao

doi:10.1007/s10409-020-00965-0

Cited by 12 publications

(3 citation statements)

References 59 publications

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“…Besides, with the increase of indentation depth, the elastic modulus and hardness of most cured monomers and their composites are not constant but increase gradually with the decrease of load (indenter displacement) within a certain range (as shown in Figure S2a,b). This phenomenon, called the size effect of nanoindentation, can be explained by the strain gradient plasticity theory developed based on the molecular kinking mechanism. , Its size effect is mainly caused by size-related deformation. The degree of size-dependent deformation is affected by the bending stiffness, molecular weight, crosslinking density, and flexibility of the polymer molecular chain.…”

Section: Resultsmentioning

confidence: 99%

“…This phenomenon, called the size effect of nanoindentation, can be explained by the strain gradient plasticity theory developed based on the molecular kinking mechanism. 42,43 Its size effect is mainly caused by sizerelated deformation. The degree of size-dependent deformation is affected by the bending stiffness, molecular weight, crosslinking density, and flexibility of the polymer molecular chain.…”

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Phosphorus-Containing Flame-Retardant Benzocyclobutylene Composites with High Thermal Stability and Low CTE

et al. 2023

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As a component of printed circuit substrate, copper clad laminate (CCL) needs to meet the performance requirements of heat resistance, flame retardancy, and low coefficient of thermal expansion (CTE), which, respectively, affects the stability, safety, and processability of terminal electronic products. In this paper, benzocyclobutylene (BCB)-functionalized phosphorus−oxygen flame retardant composites were prepared through introducing the BCB groups, and the performance was researched by thermogravimetric analysis, microcombustion calorimetry, and thermomechanical analysis. The research results show that these phosphorus oxide compounds containing BCB groups show good thermal stability and low total heat release (THR) after thermal curing, and the more BCB groups on the phosphorus oxide monomers, the better the thermal stability and flame retardancy of cured resins. The T d5 and THR of the composite (M3) are as high as 443 °C and 23.1 kJ/g, respectively. In addition, the CTE of M3 is as low as 16.71 ppm/°C. Introduction of BCB groups which can be crosslinked through heat to improve the thermal stability, flame retardancy, and reduced CTE of traditional organophosphorus flame retardant materials. These materials are expected to be good candidates for CCL substrates for electronic circuits.

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Phosphorus-Containing Flame-Retardant Benzocyclobutylene Composites with High Thermal Stability and Low CTE

et al. 2023

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“…通过上式即可拟合细丝扭转的实验数据。Liu 等人 [116] 对 Chen-Wang [114] 以及 Aifantis [112] 的应变梯度塑性理论进行了上述同样的讨论。将这 3 种应变梯度塑性理论与扭转结果进行比较，发现 Fleck-Hutchinson 和 Chen-Wang 模型能够预测扭转时细丝屈服强度的升高，而 Aifantis 模型却不能预测该尺寸效应。Liu 等人 [116] 认为这与 Aifantis 模型的应变依赖性有关。同时，这 3 种模型的材料内在特征尺寸参数 l 不仅需要通过实验数据来确定，还与模型中的参数有关(如 Fleck-Hutchinson 模型中的耦合系数 μ) 。基于前人的工作，许多学者对细丝扭转问题进行了进一步的研究。Ban 等人 [117] 在传统 SGP 理论基础上，提出了一种改进的增量本构模型，以表征微金属材料中尺寸和损伤的耦合效应。该模型考虑了小应变和各向同性损伤的假设，包含了服役过程中的变形损伤对弹性模量、塑性屈服准则和材料内在特征尺寸的影响。他们应用新的修正理论分析了细铜丝扭转的实验结果，表明理论预测与实验测量结果吻合较好。Liu 等人 [118] 研究了材料固有长度尺度的塑性应变依赖性的 3 种不同关系，并将该理论应用于丝材扭转测试。通过比较现有的和新建立的本构方程，他们发现一个逐渐减小的材料内在特征尺寸参数比恒定的材料内在特征尺寸参数对丝材的扭矩有更好的预测。作者还讨论了泰勒位错规则及其对推导本构方程的影响。Ding 等人 [119] 讨论了铜微米丝的尺寸依赖性扭转变形，并提出了基于 Gudmundson 高阶 SGP 理论热力学框架 [109] 的增量式高阶 SGP 本构模型来描述这一现象。该模型引入了一种新的随动硬化演化规则，考虑了样品和晶粒的尺寸对塑性硬化的耦合效应。有限元仿真结果表明，该模型能够准确捕捉铜微米丝尺寸相关的扭转变形。Hua 等人 [120]…”

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Mechanical behavior and deformation mechanism of <?A3B2 ACK?>high-strength metallic wires

Chen,

Xu,

Dai

et al. 2024

Chin. Sci. Bull.

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Metallic wires, as a distinctive type of structural and functional materials, have a long history and play irreplaceable roles in the fields of energy, transportation, marine vessels and so on. With the development of national strategic demands, the new generation of major equipment faces challenges in extreme service environments, such as deep space, deep sea and polar regions, and the corresponding harsh application scenarios, i.e., high-speed impact, cryogenic temperature and corrosion, etc., pose significant challenges to the service reliability of high-strength metallic wires. Therefore, not only to provide adequate supports for most challenged structural applications, but also to save material cost, developing high-performance metallic wires and revealing their mechanical behavior have been pressing and vital subjects. Up to date, researchers have invented numerous wire preparation technologies, including the drawing method, glass coated method, rotating water melt-spinning method, melt-extraction method and drawing method in the supercooled liquid region, leading to the emergence of various high-performance metallic wires, such as traditional pearlitic steel wires, amorphous alloy wires and high entropy alloy wires, etc. Among high-strength metallic wires, conventional pearlitic steel wires currently hold the world record for the highest tensile strength of metallic wires, while novel high entropy alloy wires have successfully addressed the strength-ductility trade-off dilemma among traditional wires, as well as the issues of low-temperature brittleness, showing great application potential under harsh service circumstances. Due to the different microstructures and physical and chemical properties, different types of metallic wires exhibit unique mechanical behaviors and complex plastic deformation mechanisms. The high strength of polycrystalline alloy wires, e.g., pearlitic steel wires and high entropy alloy wires, primarily arises from multiple strengthening mechanisms, such as boundary hardening, dislocation hardening, precipitation strengthening, etc., while the high strength of amorphous alloy wires stems from their intrinsic atomic disordered structures. The plastic deformation of polycrystalline alloy wires is characterized by a variety of complex plastic deformation mechanisms, including dislocation motion, propagation of stacking faults, deformation twinning, phase transformation and their interactions, while the plastic deformation of amorphous alloy wires is mainly related to the activation and aggregation of flow defects. In order to further enhance the strength and ductility of metallic wires, researchers have proposed amounts of effective methods, such as regulating alloy composition, refining microstructures and designing non-uniform structures. As the diameter of metallic wire decreases, a deformation size effect become apparent, then the strain-gradient plasticity theory that considers this size effect has been developed and effectively applied to describe the mechanical behavior of these m...

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Microstructural effects on overall dynamics of composites: an analytical method via spatiotemporal nonlocal model

Wang¹,

Zhang²,

Wang³

2022

Arch Appl Mech

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On dissipative gradient effect in higher-order strain gradient plasticity: the modelling of surface passivation

Cited by 12 publications

References 59 publications

Phosphorus-Containing Flame-Retardant Benzocyclobutylene Composites with High Thermal Stability and Low CTE

Phosphorus-Containing Flame-Retardant Benzocyclobutylene Composites with High Thermal Stability and Low CTE

Mechanical behavior and deformation mechanism of <?A3B2 ACK?>high-strength metallic wires

Microstructural effects on overall dynamics of composites: an analytical method via spatiotemporal nonlocal model

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On dissipative gradient effect in higher-order strain gradient plasticity: the modelling of surface passivation

Cited by 12 publications

References 59 publications

Phosphorus-Containing Flame-Retardant Benzocyclobutylene Composites with High Thermal Stability and Low CTE

Phosphorus-Containing Flame-Retardant Benzocyclobutylene Composites with High Thermal Stability and Low CTE

Mechanical behavior and deformation mechanism of &lt;?A3B2 ACK?&gt;high-strength metallic wires

Microstructural effects on overall dynamics of composites: an analytical method via spatiotemporal nonlocal model

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Mechanical behavior and deformation mechanism of <?A3B2 ACK?>high-strength metallic wires