Effects of Powder Size and Shape on Microstructure of Al Thin Plate Formed by Compression Shearing Method at Room Temperature

昇, 中山; 将臣, 堀田; 寛之, 三木; 孝道, 宮崎; 洋征, 武石

doi:10.9773/sosei.54.191

Cited by 4 publications

(5 citation statements)

References 9 publications

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“…COSME-RT is used to form thin metal plates by applying a shear strain and a compression stress to a metal powder at room temperature and in air [8][9][10][11][12][13][14][15]. In COSME-RT, the metal powders obtain a bonding energy in a mechanical process with strains in two axial directions, and without heating.…”

Section: Introductionmentioning

confidence: 99%

“…In COSME-RT, powder material with a fine crystalline structure is used as a starting material and its small crystalline structure is retained during the forming process [8]. When pure Al or pure Ti powder are used as the material powder, the material grain size becomes finer than that of the starting materials by application of a large strain as a severe plastic deformation technique [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

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Cu-Based MoS2-Dispersed Composite Material Formed by the Compression Shearing Method at Room Temperature

et al. 2017

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Cu/MoS 2 composite material was formed by a novel powder-molding technique, which is termed the compression shearing method at room temperature (COSME-RT). Cu/MoS 2 sample mechanical and tribological properties and microstructures were investigated. Samples were prepared using five different MoS 2 concentrations between 0 to 20 vol.%. No unwanted compounds were generated by the Cu and MoS 2 because a high temperature is unnecessary in COSME-RT. Scanning electron microscopy observations confirmed that the MoS 2 particles were dispersed homogeneously in the Cu host matrix. The indentation hardness of Cu/MoS 2 with 0, 1.0 and 5.0 vol.% MoS 2 was higher than 1.6 GPa, and is higher than that formed by conventional powder metallurgy methods and a pure Cu plate. The indentation hardness of the Cu/MoS 2 decreased with increasing MoS 2 concentration. In contrast, the lubricating performance of MoS 2 became more pronounced at 5.0 vol.% or above. The coefficient of friction of Cu/MoS 2 with 5.0, 10 and 20 vol.% MoS 2 was ~0.20, and is the same as for MoS 2 in air. The sample coefficient of friction was maintained because of lubrication by forming a transferred film of wear debris that contained MoS 2 . Cu/MoS 2 had a low coefficient of friction, but maintained its material strength at 5.0 vol.% MoS 2 .

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cu-Based MoS2-Dispersed Composite Material Formed by the Compression Shearing Method at Room Temperature

et al. 2017

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“…Several methods to form composites, such as powder metallurgy and casting-based methods have been attempted to achieve such requirements [1][2][3][4][5][6][7]. In recent years, our research group has focused on a novel powder-molding method, the compression shearing method at room temperature (COSME-RT) [8][9][10][11][12][13][14][15][16][17][18][19], to meet the material requirements. COSME-RT is used to form a thin plate by applying a simultaneous compressive stress and shearing strain to a powder material at room temperature and in an ambient atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Role of MoS2 Addition in the Consolidation of Metal from Powder to Plate by the Compression Shearing Method at Room Temperature

et al. 2018

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We use a Cu/MoS 2 composite to provide a new approach to control the consolidation of materials by compression-shearing at room temperature. Cu/MoS 2 samples were formed under several shearing distances and the resulting microstructures were observed and compared with pure Cu samples. The microstructural change related to the decrease in applied shearing force is discussed. The structural observations indicate that the reason for the decrease in shearing force appears to be the slip of the sample on the lower plate because of MoS 2 lubrication. The internal structure of the Cu/MoS 2 samples appears to be interrupted midway through the consolidation process by dissipating the applied shearing force. In contrast, particle bonding and grain refinement occurred only on the sample surface, as for the friction process, and extended gradually to the inside of the sample when the shearing distance increased. We controlled the metal consolidation by compression shearing at room temperature by dispersing MoS 2 into a Cu matrix. The shearing force appears to be more effective in metal consolidation by compression shearing at room temperature than the shearing distance.

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“…Several methods for forming metals such as powder metallurgy and casting have been attempted to develop alternative metals and alloys [2][3][4][5]. Our research group has focused on a novel powder molding method, based on a compression shearing method at room temperature (COSME-RT) [6][7][8][9][10][11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

“…It differs from conventional metal molding methods, because a high-temperature process is not required, and materials can be formed without coarsening of their crystal grains [6] or formation of any compounds [16]. The grain size of the material becomes finer than that of the feedstock powder owing to the large applied strain, as shown by previous studies on pure Al and pure Ti [7,8]. In those cases, the formed materials showed high strength, explained by the Hall-Petch relation [18,19].…”

Section: Introductionmentioning

confidence: 99%

Interparticle Bonding of Cu Powder under Repetitive Unidirectional Friction

et al. 2018

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Unidirectional friction experiments on uniaxially compressed pure Cu powder were performed to clarify how the solid-phase interparticle bonding proceeds during a powder molding method by applying biaxial force, termed as a compression shearing method at room temperature. Relations among the applied normal load, number of sliding cycles, and microstructural changes of the powder particles were investigated by morphological and cross-sectional observations of the samples after the friction experiments. The structural observations revealed some layered regions with different microstructures within the sample cross-section. All regions increased in size at a higher applied normal load, but their size did not change as the number of the sliding cycles increased. This phenomenon was quantitatively explained by Hamilton and Goodman's model, which showed that the applied normal load correlated with the stress distribution applied to the sample. Tensile stress applied to the powder particles along the sliding direction appeared to be most effective for interparticle bonding. In addition, it was suggested that the bonding process of the powder particles proceeded through the steps: (1) plastic deformation; (2) initially crystal grain refinement to micrometer size; (3) bonding by local sliding between powder particles; and (4) crystal grain refinement to sub-micrometer size.

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Effects of Powder Size and Shape on Microstructure of Al Thin Plate Formed by Compression Shearing Method at Room Temperature

Cited by 4 publications

References 9 publications

Cu-Based MoS<sub>2</sub>-Dispersed Composite Material Formed by the Compression Shearing Method at Room Temperature

Cu-Based MoS<sub>2</sub>-Dispersed Composite Material Formed by the Compression Shearing Method at Room Temperature

Role of MoS<sub>2</sub> Addition in the Consolidation of Metal from Powder to Plate by the Compression Shearing Method at Room Temperature

Interparticle Bonding of Cu Powder under Repetitive Unidirectional Friction

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