Miyamae ku, Japan
Miyamae ku, Japan

Time filter

Source Type

Mizuuchi K.,Osaka Institute of Technology | Inoue K.,University of Washington | Agari Y.,Osaka Institute of Technology | Sugioka M.,Osaka Institute of Technology | And 6 more authors.
Advanced Materials Research | Year: 2014

Diamond-particle-dispersed aluminum (Al) matrix composites consisting of monomodal and bimodal diamond particles were fabricated in spark plasma sintering process, where the mixture of diamond, pure Al and Al-5mass% Si alloy powders were consolidated in liquid and solid co-existent state. Microstructures and thermal properties of the composites fabricated in such a unique way were investigated and the bimodal and monomodal diamond particle effect was evaluated on the thermal properties of the composites. The composites can be well consolidated in a temperature range between 773 K and 878 K and scanning electron microscopy detects no reaction product at the interface between the diamond particle and the Al matrix. Relative packing density of the composite containing monomodal diamond particles decreased from 99.1% to 87.4% with increasing volume fraction of diamond between 50% and 60%, whereas that of the composite containing bimodal diamond particles was higher than 99% in a volume fraction of diamond up to 65%. The thermal conductivity of the composite containing bimodal diamond particles was higher than that of the composite containing monomodal diamond particles in a volume fraction of diamond higher than 60% and the thermal conductivity of the composite containing 70 vol.% bimodal diamond particles was 578 W/mK at R.T. © (2014) Trans Tech Publications, Switzerland.


Mizuuchi K.,Osaka Municipal Technical Research Institute | Inoue K.,University of Washington | Agari Y.,Osaka Municipal Technical Research Institute | Sugioka M.,Osaka Municipal Technical Research Institute | And 6 more authors.
Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy | Year: 2013

Silicon carbide (SiC)-particle-dispersed-aluminum (Al) matrix composites were fabricated in continuous solidliquid co-existent state by Spark Plasma Sintering (SPS) process from the mixture of SiC powders, Al powders and Al-5mass%Si alloy powders. As the SiC powders, two kind of powders, monomodal SiC powders of 109.8μm in diameter and a bimodal SiC powder mixture of 109.8/zm and 14.3μm in diameter, were used. The microstructures and thermal conductivities of the composites fabricated were examined. These composites were all well consolidated by heating at a temperature range between 798 K and 876 K for 1.56 ks during SPS process. No reaction at the interface between the SiC particle and the Al matrix was observed by scanning electron microscopy for the composites fabricated under the sintering conditions employed in the present study. Although the relative packing density of the monomodal composite decreased from 99.8 % to 95.1 % with increasing SiC volume fraction between 55 % and 65 %, that of the bimodal composite was higher than 97 % in a SiC volume fraction range up to 70 %. The thermal conductivity of the bimodal composite was higher than that of the monomodal composite in a SiC volume fraction range higher than 60 %. The coefficient of thermal expansion of the composites falls in the upper line of Kemer's model, indicating strong bonding between the SiC particle and the Al matrix in the composite.


Mizuchi K.,Osaka Municipal Technical Research Institute | Inoue K.,University of Washington | Agari Y.,Osaka Municipal Technical Research Institute | Sugioka M.,Osaka Municipal Technical Research Institute | And 6 more authors.
Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy | Year: 2013

Diamond-particle-dispersed-silver (Ag) matrix composites were fabricated in solid-liquid co-existent state by Spark Plasma Sintering (SPS) process from the mixture of diamond powders, Ag powders and Si powders. As the diamond powders, two kind of powders, monomodal diamond powders of 310μm in diameter and a bimodal diamond powder mixture of 310μm and 34.8μm in diameter, were used. The microstructures and thermal conductivities of the composites fabricated were examined. These composites were all well consolidated by heating at a temperature range between 1113 K and 1188 K for 0.45 ks during SPS process. No reaction at the interface between the diamond particle and the Ag matrix was observed by scanning electron microscopy for the composites fabricated under the sintering conditions employed in the present study. Although the relative packing density of the monomodal composite decreased from 97.4% to 93.4% with increasing diamond volume fraction between 50% and 60%, that of the bimodal composite was higher than 97% in a diamond volume fraction range up to 65 %. The thermal conductivity of the bimodal composite was higher than that of the monomodal composite in a diamond volume fraction range between 55 % and 65 %. The coefficient of thermal expansion of the composites falls in the upper line of Kerner's model, indicating strong bonding between the diamond particle and the A1 matrix in the composite.


Mizuuchi K.,Osaka Municipal Technical Research Institute | Inoue K.,University of Washington | Agari Y.,Osaka Municipal Technical Research Institute | Nagaoka T.,Osaka Municipal Technical Research Institute | And 7 more authors.
Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy | Year: 2012

β-SiC-particle-dispersed-aluminum (Al) matrix composite was fabricated in the solid-liquid co-existent state by the Spark Plasma Sintering (SPS) process from the mixture of β-SiC powders, Al powders and Al-5mass%Si powders. The microstructures and thermal conductivities of the composites fabricated were examined. These composites were all well consolidated by heating at a temperature range between 798 K and 876 K for 1.56 ks during the SPS process. No reaction at the interface between the β-SiC particle and the Al matrix was observed by scanning electron microscopy for the composites fabricated under the sintering conditions employed in the present study. The relative packing density of the Al/β-SiC composite fabricated was higher than 99 % in a volume fraction range of SiC between 40% and 50%. Thermal conductivity of the Al/β-SiC composite was higher than 200 W/mK in a β-SiC volume fraction range between 40 and 50 vol%. The highest thermal conductivity was obtained for Al-45 vol%β-SiC composite and reached 216 W/mK. The coefficient of thermal expansion of the composites falls in the upper line of Kemer's model, indicating strong bonding between the β-SiC particle and the Al matrix in the composite.


Mizuuchi K.,Osaka Municipal Technical Research Institute | Inoue K.,University of Washington | Agari Y.,Osaka Municipal Technical Research Institute | Sugioka M.,Osaka Municipal Technical Research Institute | And 5 more authors.
Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy | Year: 2012

Diamond-particle-dispersed-aluminum (Al) matrix composites were fabricated in a solid-liquid co-existent state by Spark Plasma Sintering (SPS) process from the mixture of diamond powders, Al powders and Al-5mass%Si powders. As the diamond powders, two kinds of powders, monomodal diamond powders of 310μm in diameter and a bimodal diamond powder mixture of 310μm and 34.8μm in diameter, were used. The microstructures and thermal conductivities of the composites fabricated were examined. These composites were all well consolidated by heating in a temperature range between 798 K and 876 K for 1.56ks during the SPS process. No reaction at the interface between the diamond particle and the Al matrix was observed by scanning electron microscopy for the composites fabricated under the sintering conditions employed in the present study. Although the relative packing density of the monomodal composite decreased from 99.1 % to 87.4% with increasing the diamond volume fraction in a diamond volume fraction range between 50% and 60%, that of the bimodal composite was higher than 99% in a diamond volume fraction range up to 65 %. The thermal conductivity of the bimodal composite was 455-581 W/mK, which is higher than that of the monomodal composite in a diamond volume fraction range higher than 60%, and it is 530-581 W/mK in a diamond volume fraction range between 60 and 70 vol%.


Mizuuchi K.,Osaka Municipal Technical Research Institute | Inoue K.,University of Washington | Agari Y.,Osaka Municipal Technical Research Institute | Sugioka M.,Osaka Municipal Technical Research Institute | And 6 more authors.
Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy | Year: 2014

cBN-particle-dispersed-aluminum (AI) matrix composites were fabricated in solid-liquid co-existent state by Spark Plasma Sintering (SPS) process from the mixture of cBN powders, AI powders and Al-5mass%Si powders. The microstructures and thermal conductivities of the composites fabricated were examined. These composites were all well consolidated by heating at a temperature range between 798 K and 876 K for 1.56 ks during SPS process. No reaction at the interface between the cBN particle and the AI matrix was observed by scanning electron microscopy for the composites fabricated under the sintering conditions employed in the present study. The relative packing density of the Al/cBN composite fabricated at a pressure of 300 MPa was higher than 99% in a volume fraction range of cBN between 35% and 50%. Thermal conductivity of the Al/cBN composite increased with increasing the cBN content in the composite in a volume fraction range between 35 and 45 vol%. The highest thermal conductivity was obtained for Al-45 vol%cBN composite and reached 305 W/mK. The coefficients of thermal expansion of the composites were a little higher than the theoretical values estimated by the upper line of Kerner's model, indicating the bonding between the cBN particle and the AI matrix in the composite is weak a little.


Mizuuchi K.,Osaka Municipal Technical Research Institute | Inoue K.,University of Washington | Agari Y.,Osaka Municipal Technical Research Institute | Kawahara M.,Fuji Electronic Industrial Co. | And 2 more authors.
Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy | Year: 2011

High-performance thermal management materials should have high thermal conductivities and low coefficients of thermal expansion (CTE) for maximizing heat dissipation and minimizing thermal stress and warping, which are critical issues in packaging of power semiconductors, light-emitting diodes and micro electro mechanical systems. Thermal stress and warping arise from CTE differences, which become significant in advanced electronic devices because of high heat generated, for example, when high-power laser diodes or high integration level of IC are in use. To ensure ideal or desired performance and adequate life of these electronic devices, it is necessary to decrease the junction temperature between two components to temperatures lower than: 398 K for military and automobile logic devices; and 343 K for some commercial logic devices. In the case of high-power density devices, the allowable temperature range is limited in the package base and die-attach thermal resistances. In any cases, the development of thermal management materials is significant in electronics fields. In order to fabricate high-performance thermal management materials with ultra-high thermal conductivities and low CTEs, we have recently initiated a series of investigations, where metal-matrix composites (MMCs) containing high thermal conductive fillers were uniquely fabricated. In our study, to avoid the damage of filler particle surfaces, spark plasma sintering (SPS) processing was used as a processing technique. In the present review, thermal properties of particle dispersed MMCs fabricated using SPS process in our recent works are introduced in comparison with those produced using various fabrication techniques by other researchers.


Mizuuchi K.,Osaka Municipal Technical Research Institute | Inoue K.,University of Washington | Agari Y.,Osaka Municipal Technical Research Institute | Sugioka M.,Osaka Municipal Technical Research Institute | And 6 more authors.
Microelectronics Reliability | Year: 2014

Diamond-particle-dispersed aluminum (Al) matrix composites consisting of monomodal and bimodal diamond particles were fabricated in spark plasma sintering process, where the mixture of diamond, pure Al and Al-5 mass% Si alloy powders were consolidated in liquid and solid co-existent state. Microstructures and thermal properties of the composites fabricated in such a way were investigated and the monomodal and bimodal diamond particle effect was evaluated on the thermal properties of the composites. The composites can be well consolidated in a temperature range between 773 K and 878 K and scanning electron microscopy detects no reaction product at the interface between the diamond particle and the Al matrix. Relative packing density of the composite containing monomodal diamond particles decreased from 99.1% to 87.4% with increasing volume fraction of diamond between 50% and 60%, whereas that of the composite containing bimodal diamond particles was higher than 99% in a volume fraction of diamond up to 65%. The thermal conductivity of the composite containing bimodal diamond particles was higher than that of the composite containing monomodal diamond particles in a volume fraction of diamond higher than 60%. The coefficients of thermal expansion (CTEs) of the diamond-particle-dispersed Al-matrix composites fall in the upper line of Kerner model, indicating good bonding between the diamond particle and the Al matrix in the composite. The thermal conductivity of the composite containing 70 vol.% bimodal diamond particles was 578 W/m K and its CTE was 6.72 × 10-6 at R.T. © 2014 Elsevier Ltd.


Mizuuchi K.,Osaka Municipal Technical Research Institute | Inoue K.,University of Washington | Agari Y.,Osaka Municipal Technical Research Institute | Sugioka M.,Osaka Municipal Technical Research Institute | And 6 more authors.
Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy | Year: 2015

Diamond-particle-dispersed-copper (Cu) matrix composites were fabricated by spark plasma sintering (SPS) process from the mixture of diamond particles, pure-Cu and boron (B) powders. The microstructures and thermal conductivities of the composites fabricated were examined. These composites were all well consolidated at a temperature of 1173 K for 600 s by spark plasma sintering (SPS) process. No reaction at the interface between the diamond particle and the Cu matrix was observed by scanning electron microscopy and X-ray diffraction analysis for the composites fabricated under the sintering condition employed in the present study. The relative packing density of the diamond particle dispersed Cu matrix composites with B addition was 3.5-6.1 % higher than that without B addition. The thermal conductivity of the Cu/diamond composite drastically increased with B addition. The thermal conductivity of (Cu-B)-50vol%diamond composites was 594 ∼ 689 W/mK in a volume fraction range of B between 1.8 and 13.8 vol% in Cu matrix. Numerous transgranular fractures of diamond particles were observed on the bending fracture surface of diamond particle dispersed Cu matrix composites with B addition, indicating strong bonding between the diamond particle and the Cu matrix in the composite.


Yanagida A.,Tokyo Denki University | Ikeda M.,Fuji Electronic Industrial Co. | Komine H.,University of Tokyo | Yanagimoto J.,University of Tokyo
ISIJ International | Year: 2012

A method of predicting the microstructure evolution and shape in the hot forming process is important for optimizing the process conditions. To develop a new analytical model that can be used to predict microstructure behavior in the actual process, a high-speed with multistage compression testing machine is required for physical simulation of the production process and to obtain material data for the prediction model. A high-speed uniform true strain rate (∼300 s -1) was achieved by a servo-hydraulic computerdriven machine with a deviation control feedforward program. The effects of processing parameter and chemical composition of plane carbon and Nb alloyed steels on ferrite grain size were investigated. A grain size of about 1 μm was accomplished in this simulator by severe hot plastic deformation. © 2012 ISIJ.

Loading Fuji Electronic Industrial Co. collaborators
Loading Fuji Electronic Industrial Co. collaborators