Mechanical, Thermal and Electrical Properties of Lotus-Type Porous Metals

Nakajima, Hideo

doi:10.4236/msa.2018.92017

Cited by 5 publications

(5 citation statements)

References 12 publications

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“…Significant anisotropy in mechanical strength, thermal conductivity and electrical conductivity is attributed to large difference in the cross-sectional area of pores in lotus metals. 27)…”

Section: Unified Interpretation Of Anisotropy In Mechanical Strength and Physical Properties Of Lotus Metalsmentioning

confidence: 99%

Fabrication, Mechanical and Physical Properties, and Its Application of Lotus-Type Porous Metals

Nakajima

2019

Mater. Trans.

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This paper reviews recent development of fabrication methods, various mechanical and physical properties of lotus-type porous metals and its application. The porous metals are fabricated by unidirectional solidification in pressurized gas atmosphere such as hydrogen, nitrogen and oxygen. The elongated pores are evolved from insoluble gas when the melt dissolving gas is solidified. Three fabrication techniques ® mold casting, continuous zone melting and continuous casting techniques ® are introduced. The latter two techniques can control the solidification velocity and the last one possesses a merit of mass production. Anisotropy observed in mechanical and physical properties is resulted from anisotropic pore morphology. The anisotropic behavior of tensile, compressive and fatigue strength is explained in terms of stress concentration depending upon pore orientation, while that of thermal and electrical conductivities is interpreted by anisotropic electron scattering. The porous metals exhibit good sound absorption and vibration-damping properties. Several possible applications of heat sinks, golf putters, machine tools and dental implants are introduced.

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“…Significant anisotropy in mechanical strength, thermal conductivity and electrical conductivity is attributed to large difference in the cross-sectional area of pores in lotus metals. 27)…”

Section: Unified Interpretation Of Anisotropy In Mechanical Strength and Physical Properties Of Lotus Metalsmentioning

confidence: 99%

Fabrication, Mechanical and Physical Properties, and Its Application of Lotus-Type Porous Metals

Nakajima

2019

Mater. Trans.

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“…In the welding, the casting and the 3-D printing the pore formation is a problematic issue due to the degradation of the mechanical properties of the metals [1,2]. On the other hand, ordered cylindrical pores in metals are often used to improve the functional properties, such as impact energy absorption, air or water permeability, materials properties, thermal or electrical conductivity, bone regeneration, biocompatibility, and bioresorbability, etc in various engineering and medical and technologies [3][4][5][6][7][8]. The ice crystals incorporating the bubbles containing the ozone gas have also been developed for the food preservation and the sterilization [9].…”

Section: Introductionmentioning

confidence: 99%

“…The pores thus nucleated in the cellular region. The porosity in the solid is characterized by the volume fraction of the gas bubbles responsible for the microstructure of the materials [3]. Liu et al [13], Park et al [14], and Yoshimura et al [15] measured the porosity, which decreased as the solidification rate and the imposed solute gas pressure increased.…”

Section: Introductionmentioning

confidence: 99%

Scaling of inter-pore spacing of lotus-type pores

2023

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The present study is to scale the inter-pore spacing and bubble radius required for controlling the porosity of the lotus-type pores in the solid during a unidirectional solidification. The porosity in solid degrade properties of material in welding, casting and additive manufacturing, etc. On the other hand, the ordered cylindrical pores in the material are often used to improve the functional properties, such as the tensile and compression stresses, the impact and acoustic energy absorption, the permeability, and the thermal and electrical conductivity, etc. Different from the traditional minimum undercooling criterion to estimate the porosity and size of lotus-type pores, this study relevantly combines the Gibbs-Thomson equation, the Young-Laplace equation, the nucleation theory, and the Henry’s law or Sieverts’ law to scale the inter-pore spacing and the critical radius of the lotus-type pores, which are considered as the same order of the wavelength and the amplitude of the morphological instability of the solidification front, respectively. This work revises the minimum undercooling criterion which ignores the nucleating bubble on the solidification front, and conducts irrelevant evaluation of the curvature of the solidification front. The present work finds the revised scaling results and available experimental data to be in good agreement. The sizes of the pores and the porosity in the solid can be successfully controlled in advance.

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“…For instance, those can be used to predict mechanical properties of alloys 12,[16][17][18] or structured materials 19 which are correlated with process parameters, alloy components or microstructure features. A major di culty for a proper prediction often lies in the accuracy and statistical pertinence of the extracted microstructure features 20 . When relating microstructure with material properties, reliable, automated and objective segmentation as well as correct classi cation of the microstructures is required.…”

Section: Introductionmentioning

confidence: 99%

Artificial Intelligence Driven Material Design for Porous Materials

Wijaya,

Wagner,

Sartory

et al. 2023

Preprint

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In general, material properties and the underlaying microstructure are linked to each other. It is a frontier challenge to understand the associated structure-property relationship, which displays an essential ingredient for accelerated material design. Herein, we approach this issue with a unique machine learning assisted material design workflow, suitable to tailor the electrical conductivity based on the 3D microstructure or vice versa, in porous copper. Specifically, we integrate a multi-variable linear regression model for the targeted prediction and utilize a U-Net deep learning architecture to accurately classify the collected 3D image data. The evaluated 3D microstructure features and the electrical conductivity are used as an input for the prediction model. We show that the prediction reaches a maximum r-squared value of about 0.94. Our results highlight the importance of accurately retrieving a set of physical scrutinized microstructure features with statistical confidence, a key to conclude about the microstructure-property relationship.

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Mechanical, Thermal and Electrical Properties of Lotus-Type Porous Metals

Cited by 5 publications

References 12 publications

Fabrication, Mechanical and Physical Properties, and Its Application of Lotus-Type Porous Metals

Fabrication, Mechanical and Physical Properties, and Its Application of Lotus-Type Porous Metals

Scaling of inter-pore spacing of lotus-type pores

Artificial Intelligence Driven Material Design for Porous Materials

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