The Experts below are selected from a list of 46560 Experts worldwide ranked by ideXlab platform
Katsuyoshi Kondoh - One of the best experts on this subject based on the ideXlab platform.
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Regulation of interface between carbon nanotubes-aluminum and its Strengthening Effect in CNTs reinforced aluminum matrix nanocomposites
Carbon, 2019Co-Authors: Xin Zhang, Deng Pan, Bo Pan, Liu Lei, Xiaodong Hou, Mingqiang Chu, Katsuyoshi Kondoh, Maiqun ZhaoAbstract:Abstract Carbon nanotubes (CNTs) are popular as the chosen reinforcement to achieve excellent mechanical and functional performance in aluminum matrix nanocomposites (AMNCs). However, the key bottleneck problems restrict the Strengthening Effect using CNTs in AMNCs due to the dispersion homogeneity of CNTs, the distinct differences in physical properties, poor wettability and interface bonding between CNTs and aluminum matrix. This study aims to address these key issues by introducing a continuous SiC nano layer on CNTs surface synthesized from carbon-silicon reaction, acting as a compatibility transition layer prior to mixing with aluminum powders. The results clearly show that the SiC cladding layer provides a good wettability and strong interfacial bonding between CNTs and aluminum matrix, and the interfacial reaction between CNTs and aluminum matrix could be Effectively regulated. It is also conducive to reducing the mass density difference and specific surface energy, improving the dispersion of CNTs in matrix. Those factors make a strong contribution to the Strengthening Effect of CNTs enforcement by achieving high load transfer efficiency. The AMNCs reinforced by this new CNTs/SiC composite powder show clear improvement of mechanical performance without compromising in ductility and electrical conductivity, as compared to AMNCs reinforced by only CNTs or SiC.
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A novel Strengthening Effect of in-situ nano Al2O3w on CNTs reinforced aluminum matrix nanocomposites and the matched Strengthening mechanisms
Journal of Alloys and Compounds, 2018Co-Authors: Xin Zhang, Deng Pan, Bo Pan, Shengyin Zhou, Shenghui Yang, Lei Jia, Katsuyoshi KondohAbstract:Abstract Nano alumina whiskers (Al2O3w) were in-situ synthesized in carbon nanotubes (CNTs) reinforced aluminum matrix nanocomposites (AMNCs) which were fabricated by flake powder metallurgy (P/M). To study the Strengthening Effect of nano Al2O3w on CNTs reinforced AMNCs and clarify the Strengthening mechanisms, the microstructures and mechanical properties of AMNCs are investigated. It is found that CNTs-Al2O3w reinforcements have a significant hybrid Strengthening Effect on tensile strength due to their uniform dispersion and good interfacial bonding with Al matrix. The Strengthening mechanisms of CNTs-Al2O3w reinforcements are considered as a sum of load transfer, grain refinement, thermal mismatch and Orowan looping theory. The experimental strengths of AMNCs containing 0.25 and 0.5 vol% CNTs are well matched with the theoretical values calculated by the Strengthening mechanisms. And the differences between them are less than 2.9%, which is highly Effective for predicting the mechanical properties of CNTs-Al2O3w reinforced AMNCs. The predicted values indicate that load transfer mechanism from both CNTs and Al2O3w is dominant, improving UTS of 0.5CNTs reinforced flake AMNCs (228 MPa) by more than 79.5% in comparison with pure Al.
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stability of Strengthening Effect of in situ formed ticp and tibw on the elevated temperature strength of ticp tibw ti composites
Journal of Alloys and Compounds, 2014Co-Authors: Lei Jia, Biao Chen, Hisashi Imai, Makoto Takahashi, Katsuyoshi KondohAbstract:Abstract (TiCp + TiBw)/Ti composite was firstly prepared by spark plasma sintering (SPS) and hot extrusion from Ti–B4C system, and then isothermally heat treated at 400–700 °C for 24 h, respectively. The elevated temperature tensile strength was tested at temperatures corresponding to isothermal heat treatments. Microstructure characterizations were carried out by using SEM, EPMA, XRD, EBSD and TEM. Results show that, the microstructure of (TiCp + TiBw)/Ti composite consists of Ti matrix, particle-like TiC and whisker-like TiB. TiCp and TiBw are stable at elevated temperatures and can prevent Ti matrix from coarsening. On the other hand, the strength of the composite decreases significantly with the increase of testing temperature, but it is always in proportion to that of pure Ti tested at the same temperature, indicating the Strengthening Effect of in situ formed TiCp and TiBw is stable at elevated temperature. The decrease of elevated temperature strength of (TiCp + TiBw)/Ti composite can be mainly attributed to the high temperature softening of Ti matrix.
Lei Jia - One of the best experts on this subject based on the ideXlab platform.
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A novel Strengthening Effect of in-situ nano Al2O3w on CNTs reinforced aluminum matrix nanocomposites and the matched Strengthening mechanisms
Journal of Alloys and Compounds, 2018Co-Authors: Xin Zhang, Deng Pan, Bo Pan, Shengyin Zhou, Shenghui Yang, Lei Jia, Katsuyoshi KondohAbstract:Abstract Nano alumina whiskers (Al2O3w) were in-situ synthesized in carbon nanotubes (CNTs) reinforced aluminum matrix nanocomposites (AMNCs) which were fabricated by flake powder metallurgy (P/M). To study the Strengthening Effect of nano Al2O3w on CNTs reinforced AMNCs and clarify the Strengthening mechanisms, the microstructures and mechanical properties of AMNCs are investigated. It is found that CNTs-Al2O3w reinforcements have a significant hybrid Strengthening Effect on tensile strength due to their uniform dispersion and good interfacial bonding with Al matrix. The Strengthening mechanisms of CNTs-Al2O3w reinforcements are considered as a sum of load transfer, grain refinement, thermal mismatch and Orowan looping theory. The experimental strengths of AMNCs containing 0.25 and 0.5 vol% CNTs are well matched with the theoretical values calculated by the Strengthening mechanisms. And the differences between them are less than 2.9%, which is highly Effective for predicting the mechanical properties of CNTs-Al2O3w reinforced AMNCs. The predicted values indicate that load transfer mechanism from both CNTs and Al2O3w is dominant, improving UTS of 0.5CNTs reinforced flake AMNCs (228 MPa) by more than 79.5% in comparison with pure Al.
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stability of Strengthening Effect of in situ formed ticp and tibw on the elevated temperature strength of ticp tibw ti composites
Journal of Alloys and Compounds, 2014Co-Authors: Lei Jia, Biao Chen, Hisashi Imai, Makoto Takahashi, Katsuyoshi KondohAbstract:Abstract (TiCp + TiBw)/Ti composite was firstly prepared by spark plasma sintering (SPS) and hot extrusion from Ti–B4C system, and then isothermally heat treated at 400–700 °C for 24 h, respectively. The elevated temperature tensile strength was tested at temperatures corresponding to isothermal heat treatments. Microstructure characterizations were carried out by using SEM, EPMA, XRD, EBSD and TEM. Results show that, the microstructure of (TiCp + TiBw)/Ti composite consists of Ti matrix, particle-like TiC and whisker-like TiB. TiCp and TiBw are stable at elevated temperatures and can prevent Ti matrix from coarsening. On the other hand, the strength of the composite decreases significantly with the increase of testing temperature, but it is always in proportion to that of pure Ti tested at the same temperature, indicating the Strengthening Effect of in situ formed TiCp and TiBw is stable at elevated temperature. The decrease of elevated temperature strength of (TiCp + TiBw)/Ti composite can be mainly attributed to the high temperature softening of Ti matrix.
Di Zhang - One of the best experts on this subject based on the ideXlab platform.
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Strengthening Effect of in situ TiC particles in Ti matrix composite at temperature range for hot working
Materials Characterization, 2016Co-Authors: Zhongbing Shi, Ping Liu, Xinkuan Liu, Xiaohong Chen, He Daihua, Ke Zhang, Deng Pan, Di ZhangAbstract:Abstract In this work, hot-working behavior of Ti matrix composite reinforced with TiC particles was investigated by means of hot compression tests and metallographic techniques. The Strengthening Effect of TiC particles on flow stress was measured. It was found that there is an about 100 K increase in βt of the 5 vol.% in situ TiC reinforced Ti-1100 composite compared to that of the monolithic Ti-1100 alloy. The incorporation of TiC particles increased the flow stress significantly. Sharp decreases in flow stress are observed at 10 − 1 s − 1 or 10 − 2 s − 1 strain rates and 1373 K or 1423 K during hot compression. An improved model was used to characterize the Strengthening Effect of ceramic reinforcement in term of threshold stress. The calculated values of deformation activation energy and threshold stress vary with test temperature from 1273 to 1423 K, and the threshold stress of the composite decreases from 70 MPa to 18 MPa. Besides the Effect of temperature, the great variation of threshold stress may result from the transformation of αphase to βphase partly.
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synergistic Strengthening Effect of graphene carbon nanotube hybrid structure in aluminum matrix composites
Carbon, 2015Co-Authors: Zan Li, Zhiqiang Li, Yishi Su, Di ZhangAbstract:Abstract High-performance reinforcement and tailored architecture are currently explored to develop advanced metal matrix composites. In this work, aluminum (Al) matrix composite reinforced by hybrid carbon nanofillers was fabricated by a composite flake assembly process. It was found that for various carbon nanofiller volume fractions, a striking synergistic Strengthening Effect was achieved by employing graphene (reduced graphene oxide, RGO) and carbon nanotube (CNT) hybrid structure as reinforcement in the Al matrix. Particularly, a tensile strength of 415 MPa was achieved with the addition of 1.5 vol.% of RGO-CNT hybrid, which is significantly higher than those reinforced by individual CNT or RGO (326 and 331 MPa, respectively). The synergistic Strengthening Effect was attributed to the formation of a planar network of RGO and CNT, which improves the load transfer efficiency between the matrix and the reinforcement in composites. Our study highlights the importance of reinforcement architecture for enhancing the Strengthening ability in composites, and provides an Effective route to fully take the advantage of the superior properties of various reinforcements.
B.l. Xiao - One of the best experts on this subject based on the ideXlab platform.
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origin of insignificant Strengthening Effect of cnts in t6 treated cnt 6061al composites
Acta Metallurgica Sinica (english Letters), 2018Co-Authors: Ke Zhao, Zhenyu Liu, B.l. XiaoAbstract:Carbon nanotube (CNT)-reinforced 6061Al (CNT/6061Al) composites were fabricated via powder metallurgy combined with friction stir processing (FSP). CNTs were dispersed after FSP and accelerated the precipitation process of the CNT/6061Al composites. However, the Strengthening Effect of CNTs on the T6-treated materials was insignificant, while the composites under the FSP and solution treatment conditions exhibited increased strength compared to the matrix. Precipitate-free zones (PFZs) were detected around CNTs in the T6-treated CNT/6061Al composites, and a model was proposed to describe the Effect of PFZs on strength. The calculations indicated that the strength of PFZs was similar to that of the T6-treated 6061Al. As a result, the Strengthening Effect of CNTs on the T6-treated CNT/6061Al composites was insignificant.
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Origin of Insignificant Strengthening Effect of CNTs in T6-Treated CNT/6061Al Composites
Acta Metallurgica Sinica (English Letters), 2017Co-Authors: Ke Zhao, Liu Zhenyu, B.l. Xiao, Ni DingruiAbstract:Carbon nanotube (CNT)-reinforced 6061Al (CNT/6061Al) composites were fabricated via powder metallurgy combined with friction stir processing (FSP). CNTs were dispersed after FSP and accelerated the precipitation process of the CNT/6061Al composites. However, the Strengthening Effect of CNTs on the T6-treated materials was insignificant, while the composites under the FSP and solution treatment conditions exhibited increased strength compared to the matrix. Precipitate-free zones (PFZs) were detected around CNTs in the T6-treated CNT/6061Al composites, and a model was proposed to describe the Effect of PFZs on strength. The calculations indicated that the strength of PFZs was similar to that of the T6-treated 6061Al. As a result, the Strengthening Effect of CNTs on the T6-treated CNT/6061Al composites was insignificant.
Hisashi Imai - One of the best experts on this subject based on the ideXlab platform.
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stability of Strengthening Effect of in situ formed ticp and tibw on the elevated temperature strength of ticp tibw ti composites
Journal of Alloys and Compounds, 2014Co-Authors: Lei Jia, Biao Chen, Hisashi Imai, Makoto Takahashi, Katsuyoshi KondohAbstract:Abstract (TiCp + TiBw)/Ti composite was firstly prepared by spark plasma sintering (SPS) and hot extrusion from Ti–B4C system, and then isothermally heat treated at 400–700 °C for 24 h, respectively. The elevated temperature tensile strength was tested at temperatures corresponding to isothermal heat treatments. Microstructure characterizations were carried out by using SEM, EPMA, XRD, EBSD and TEM. Results show that, the microstructure of (TiCp + TiBw)/Ti composite consists of Ti matrix, particle-like TiC and whisker-like TiB. TiCp and TiBw are stable at elevated temperatures and can prevent Ti matrix from coarsening. On the other hand, the strength of the composite decreases significantly with the increase of testing temperature, but it is always in proportion to that of pure Ti tested at the same temperature, indicating the Strengthening Effect of in situ formed TiCp and TiBw is stable at elevated temperature. The decrease of elevated temperature strength of (TiCp + TiBw)/Ti composite can be mainly attributed to the high temperature softening of Ti matrix.
