Anisotropic Yield Behavior of Lotus-Type Porous Iron: Measurements and Micromechanical Mean-Field Analysis

Tane, Masakazu; Ichitsubo, Tetsu; Hyun, Soong‐Keun; Nakajima, Hideo

doi:10.1557/jmr.2005.0009

Cited by 35 publications

(16 citation statements)

References 18 publications

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“…Since the magnitude of stress concentration around the cylindrical pores depends on loading directions, the mechanical strengths of lotus metals show anisotropy. [6][7][8][9][10][11][12][13] For a loading along the longitudinal axis of pores, the specific strength is almost constant because stress hardly concentrates around pores. Thus, the mechanical strength of lotus metals is superior to those of conventional porous metals.…”

Section: Introductionmentioning

confidence: 99%

Fatigue Crack Initiation and Propagation in Lotus-Type Porous Copper

2008

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We studied fatigue crack initiation and propagation in lotus-type porous copper with cylindrical pores aligned in one direction. For fatigue loadings in the direction parallel to the longitudinal axis of pores, stress field in the matrix is homogeneous. Therefore, slip bands are formed all over the specimen surface. On the other hand, for the perpendicular loadings, slip bands are formed only around pores in which stress highly concentrates. Since the localized slip bands form fatigue crack, fatigue fracture occurs even when the total plastic strain range is small. Stress field in the matrix of lotus copper affects the direction of crack propagation. For the parallel loadings, a crack propagates along a straight line as well as nonporous copper. On the other hand, for the perpendicular loading, a crack propagates along a path in which stress highly concentrates. Since stress highly concentrates around anomalously large pores, fatigue cracks are preferentially formed around the large pores and cracks propagate by crossing the large pores.

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Section: Introductionmentioning

confidence: 99%

Fatigue Crack Initiation and Propagation in Lotus-Type Porous Copper

2008

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“…The results show that the measured mechanical properties, σ ys and E , relate to the mean void orientation (μ(α)) about the load axis: the more parallel (close to 90°) the stronger the part, as other authors refer to parts with elongated voids with different materials [ 86 , 87 , 88 , 89 , 90 ].…”

Section: Discussionmentioning

confidence: 81%

Extended CT Void Analysis in FDM Additive Manufacturing Components

et al. 2020

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Additive manufacturing (AM) is the term for a number of processes for joining materials to build physical components from a digital 3D model. AM has multiple advantages over other construction techniques, such as freeform, customization, and waste reduction. However, AM components have been evaluated by destructive and non-destructive testing and have shown mechanical issues, such as reduced resistance, anisotropy and voids. The build direction affects the mechanical properties of the built part, including voids of different characteristics. The aim of this work is an extended analysis of void shape by means of X-ray computed tomography (CT) applied to fused deposition modeling (FDM) samples. Furthermore, a relation between the tensile mechanical properties and digital void measurements is established. The results of this work demonstrate that void characteristics such as quantity, size, sphericity and compactness show no obvious variations between the samples. However, the angle between the main void axis and the mechanical load axis α shows a relation for FDM components: when its mean value μ(α) is around 80 (degrees) the yield strength and Young’s modulus are reduced. These results lead to the formulation of a novel criterion that predicts the mechanical behavior of AM components.

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“…26) On the other hand, that in the direction perpendicular to the pore direction decreased more rapidly following the power law formula. 27)…”

Section: Compressive Behaviormentioning

confidence: 99%

Fabrication of Porous Metals with Unidirectionally Aligned Pores by Rod-Dipping Process

et al. 2019

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Rod-dipping Process" was developed to simultaneously fabricate and strengthen porous metals with pore with unidirectionally aligned throughout their matrix. Carbon rods were dipped into a molten A6061 alloy, quenched, and processed by equal-channel angular extrusion (ECAE). The rods were subsequently removed, producing the porous metal throughout a metallic matrix. To determine the possibility of using our method to fabricate various porous metals, a theoretical equation was formulated for calculating the volume of hydrostatic pressure required for a molten metal to infiltrate the spaces between rods of various diameters and spaced at various intervals. The primary crystal was isotropic, and no reaction products were formed on the pore surfaces. Therefore, the crystal and pore growth directions could be independently controlled. By introducing an equivalent plastic strain of 1.2, the Vickers hardness values of the samples homogeneously increased to 1.5 times higher than that of the as-cast samples. Consequently, this method enabled us to fabricate porous metals with pore with unidirectionally aligned throughout their matrices and whose pore sizes, positions and volume fractions could be arbitrarily controlled. Furthermore, the metallic matrix could be simultaneously hardened by plastic deformation. [

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Anisotropic Yield Behavior of Lotus-Type Porous Iron: Measurements and Micromechanical Mean-Field Analysis

Cited by 35 publications

References 18 publications

Fatigue Crack Initiation and Propagation in Lotus-Type Porous Copper

Fatigue Crack Initiation and Propagation in Lotus-Type Porous Copper

Extended CT Void Analysis in FDM Additive Manufacturing Components

Fabrication of Porous Metals with Unidirectionally Aligned Pores by Rod-Dipping Process

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