Zhongchun Chen - Academia.edu (original) (raw)

Papers by Zhongchun Chen

Research paper thumbnail of Preparation of a Novel Antiviral Material by Mechanical Milling

Funtai oyobi fummatsu yakin, 2016

Research paper thumbnail of Determination of True Stress–Strain Curves of Sheet Metals in Post-Uniform Elongation Range

Materials transactions, 2009

Research paper thumbnail of Drying and Debinding Behavior of Extruded Pipes Containing a Water-Based Binder

Funtai oyobi fummatsu yakin, 2001

Research paper thumbnail of Special Invited Talk : Fabrication of Bulk Thermoelectric Materials by Powder Extrusion Techniques

Research paper thumbnail of Fabrication and Thermoelectric Properties of Cu-doped Bi-Te-Se Bulk Materials

Funtai oyobi fummatsu yakin, 2016

Research paper thumbnail of Optimization of selective laser melting parameters and influence of post heat treatment on microstructure and mechanical properties of maraging steel

Materials & Design, 2018

The influences of various process parameters on densification behavior, surface morphology, micro... more The influences of various process parameters on densification behavior, surface morphology, microstructure, and mechanical properties of selective laser melted (SLMed) maraging steel have been investigated. A process map for the SLM of maraging steel has been constructed. There exists a relatively large processing window, where sound products with relatively high relative density and good surface quality can be obtained. As-built specimens contained martensite matrix with trace amount of austenite phase. The quantity of austenite phase increased during aging treatment due to reversion of martensite to austenite. Solution treatment/aging resulted in elimination of the austenite phase and formation of intermetallic precipitates in the martensite matrix. The as-built and aged specimens exhibited almost the same average grain size, while solution treatment/aging resulted in grain growth of the martensite matrix and a significant change in grain orientation. The results indicated that the SLMed specimens with the building direction parallel to the loading direction had much lower elongation than those with the building direction perpendicular to the loading direction. The maximum tensile strength and hardness obtained were 2033 MPa and 618HV respectively, after solution treatment at 820 0 C for 1 hour and aging at 460 0 C for 5 hours.

Research paper thumbnail of Microstructure and mechanical properties of in situ synthesized alumina/Ba-β-alumina/zirconia composites

Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, Feb 1, 2004

ABSTRACT

Research paper thumbnail of Interfacial reaction behavior and thermal stability of barium zirconate-coated alumina fiber/alumina matrix composites

Journal of the European Ceramic Society, 2008

ABSTRACT A barium zirconate (BaZrO3) coating was incorporated onto surfaces of alumina fibers, an... more ABSTRACT A barium zirconate (BaZrO3) coating was incorporated onto surfaces of alumina fibers, and the coated alumina fiber/alumina matrix composites were prepared by hot pressing. The interfacial reactions between BaZrO3 coating and Al2O3 fiber/matrix during the consolidation resulted in formation of ZrO2 and Ba–β-Al2O3, one of nonstoichiometric hexaluminate compounds. The diffusion of Ba cations dominates the reaction process between BaZrO3 coating and Al2O3 fiber/matrix. The Ba–β-Al2O3 phase exhibited an elongated morphology due to preferred orientational growth through directional diffusion and mass transport of Ba along the basal plane. The Young's modulus and hardness of the Ba–β-Al2O3 phase were measured by nanoindentation technique to be 250 GPa and 20 GPa, respectively. The BaZrO3-coated Al2O3 fiber/Al2O3 matrix composites showed good microstructural stability during thermal exposure up to 1400 °C.

Research paper thumbnail of Fabrication of aluminum–magnesium clad composites by continuous extrusion

Materials Science and Engineering: A, 2021

Abstract Poor corrosion resistance of Mg alloys extremely limits their industrial applications. A... more Abstract Poor corrosion resistance of Mg alloys extremely limits their industrial applications. Al/Mg clad composites using Al alloy as a protective layer are expected to be an effective approach to combine good corrosion resistance and high specific strength. In this study, novel Al clad Mg composites were developed by continuously extruding 6063 Al alloy tube and AZ31 Mg alloy rod with and without preheating of Mg alloy. The Al/Mg interfacial diffusion, microstructure, texture, and flexural properties of the continuously extruded composites were investigated experimentally. The extruded composites exhibited good metallurgical bonding between Al shell and Mg core even without preheating of Mg alloy, and their fine-grained microstructure contributes to a significant enhancement in ultimate flexural strength (UFS) to 452 MPa. Preheating of Mg alloy caused complete dynamic recrystallization (DRX) of both Al shell and Mg core and modified (0001) texture of the Mg alloy, which leads to a significant improvement in the bendability of the Al/Mg composite.

Research paper thumbnail of 1A41 Study of kinematics evaluation method for total knee arthroplasty

The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME, 2015

Research paper thumbnail of Determination of True Stress–Strain Curves of Sheet Metals in Post-Uniform Elongation Range

MATERIALS TRANSACTIONS, 2009

A novel approach to determination of the true stress-strain relation in a post-uniform elongation... more A novel approach to determination of the true stress-strain relation in a post-uniform elongation range by finite element modeling has been proposed, on the basis of the variation of strain-hardening exponent (n) with strain during uniaxial tensile tests. The strain dependence of n-value can be expressed by a linear or simple quadratic function. The proposed method has been applied to several sheet metals with large differences in strain-hardening behavior. The finite element analytical results, obtained by using constitutive equations derived from a variation of n-value with strain, are in good agreement with the measured load-elongation curves. As the number of parameters is sufficient by two at the most, the optimization by an inverse analysis becomes very easy. It has been verified that the proposed method is effective to estimate the stress-strain curves of sheet metals in the post-uniform elongation range.

Research paper thumbnail of Processing and Microstructure of an All-Oxide Ceramic Composite

Materials Science Forum, 2005

An all-oxide composite consisting of alumina fiber, alumina matrix, and barium zirconate interpha... more An all-oxide composite consisting of alumina fiber, alumina matrix, and barium zirconate interphase has been investigated. The barium zirconate interphase was applied on alumina fibers through coating via a sol-gel route. The incorporation of the coatings did not significantly influence the densification behavior of the composite under hot-pressing conditions. During the processing of the composite, the barium zirconate reacted in situ with alumina fiber and alumina matrix to form Ba-β-alumina platelets with an elongated morphology, which is propitious for crack deflection and thus toughness enhancement. The results reveal that it is possible to reduce fiber strength degradation by controlling the coating and densification processes.

Research paper thumbnail of Characterization of interfacial reaction products in alumina fiber/barium zirconate coating/alumina matrix composite

Materials Characterization, 2002

Barium zirconate (BaZrO 3) is a candidate material for interface engineering of alumina fiber/alu... more Barium zirconate (BaZrO 3) is a candidate material for interface engineering of alumina fiber/alumina matrix composites. Al 2 O 3 and BaZrO 3 react at high temperatures to form a series of reaction products. The objective of this work was to characterize these reaction products and to investigate their effect on crack propagation. BaZrO 3 coating was applied on Al 2 O 3 fibers via a sol-gel route. The characterization was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The reaction products between BaZrO 3 coating and Al 2 O 3 (fibers and/or matrix) included ZrO 2 , barium monoaluminate (BaOÁAl 2 O 3) and Ba b-Al 2 O 3 (BaOÁ7.3Al 2 O 3). In hot-pressed composites, barium aluminate was mainly present in the form of Ba b-Al 2 O 3. The Ba b-Al 2 O 3 is known to have a layer-type structure, which is likely to be propitious for crack deflection. The interfacial reactions are diffusion-controlled solid-state processes, mainly depending on the diffusion of Ba cations. The Ba b-Al 2 O 3 phase can form either through direct reaction between the BaZrO 3 coating and Al 2 O 3 or through indirect reaction between a BaOÁAl 2 O 3 intermediate phase and Al 2 O 3. The BaZrO 3 coating and the reaction products between the coating and fiber/matrix provide multiple weak interfaces, which are likely to result in crack deflection and thus toughness enhancement in an all oxide composite.

Research paper thumbnail of Characterization of interfacial reaction products in alumina fiber/barium zirconate coating/alumina matrix composite

Materials Characterization, 2002

Barium zirconate (BaZrO 3) is a candidate material for interface engineering of alumina fiber/alu... more Barium zirconate (BaZrO 3) is a candidate material for interface engineering of alumina fiber/alumina matrix composites. Al 2 O 3 and BaZrO 3 react at high temperatures to form a series of reaction products. The objective of this work was to characterize these reaction products and to investigate their effect on crack propagation. BaZrO 3 coating was applied on Al 2 O 3 fibers via a sol-gel route. The characterization was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The reaction products between BaZrO 3 coating and Al 2 O 3 (fibers and/or matrix) included ZrO 2 , barium monoaluminate (BaOÁAl 2 O 3) and Ba b-Al 2 O 3 (BaOÁ7.3Al 2 O 3). In hot-pressed composites, barium aluminate was mainly present in the form of Ba b-Al 2 O 3. The Ba b-Al 2 O 3 is known to have a layer-type structure, which is likely to be propitious for crack deflection. The interfacial reactions are diffusion-controlled solid-state processes, mainly depending on the diffusion of Ba cations. The Ba b-Al 2 O 3 phase can form either through direct reaction between the BaZrO 3 coating and Al 2 O 3 or through indirect reaction between a BaOÁAl 2 O 3 intermediate phase and Al 2 O 3. The BaZrO 3 coating and the reaction products between the coating and fiber/matrix provide multiple weak interfaces, which are likely to result in crack deflection and thus toughness enhancement in an all oxide composite.

Research paper thumbnail of Microstructural evolution of reactive-sintered aluminum matrix composites

Composites Science and Technology, 2008

... a Department of Materials Science and Engineering, School of Engineering, Tohoku University, ... more ... a Department of Materials Science and Engineering, School of Engineering, Tohoku University, Aoba-yama 6-6-02, Aoba-ku, Sendai 980-8579, Japan. b Department of Mechanical Systems Engineering, Faculty of Engineering ...

Research paper thumbnail of Validation of 3-dimensional postoperative evaluation technique for Total Knee Arthroplasty

Journal of Japan Society of Computer Aided Surgery

Several surgical assistance systems for total knee arthroplasty(TKA)have been applied to enhance ... more Several surgical assistance systems for total knee arthroplasty(TKA)have been applied to enhance the surgical precision. The accuracy of these surgical assistance systems has been evaluated with regards to the implant setting posture by 2-dimensional X-ray images. It was found that these systems were effective in enhancing surgical precision as reported in several publications. On the other hand, some authors reported no significant difference between these systems and conventional operation. When using 2-dimensional X-ray images for evaluation, a wrong knee posture during image acquisition introduces an error. Therefore, we evaluated several 3-dimensional evaluation methods using CT scans. In this study, we adopted three evaluation methods for TKA：1)CT-based preplanning software, 2)3-dimensional matching using a CAD model, and 3)a surgical navigation system. The error of these evaluation methods was less than 2 mm and 2 degrees. In conclusion, 1)it is important to validate the evaluation tool for each implant geometry and／or each evaluation method, 2)a suitable evaluation method should be selected in accordance with the intended use.

Research paper thumbnail of Microstructure, Texture, and Mechanical Properties of Continuously Extruded and Rolled AZ31 Magnesium Alloy Sheets

Journal of Materials Engineering and Performance

Research paper thumbnail of 601 Mechanical Properties of Al-Al_2O_3-TiB_2 Composite Processed by Reactive Sintering and Hot-Rolling

The Proceedings of Autumn Conference of Tohoku Branch

Research paper thumbnail of 603 Formability of Al-Al_2O_3-TiC Composite Processed by Reactive Sintering and Hot Compression

The Proceedings of Autumn Conference of Tohoku Branch

Research paper thumbnail of 613 Plastic Anisotropy of A2024-O and T6 Aluminum Alloys

The Proceedings of Autumn Conference of Tohoku Branch

Research paper thumbnail of Preparation of a Novel Antiviral Material by Mechanical Milling

Funtai oyobi fummatsu yakin, 2016

Research paper thumbnail of Determination of True Stress–Strain Curves of Sheet Metals in Post-Uniform Elongation Range

Materials transactions, 2009

Research paper thumbnail of Drying and Debinding Behavior of Extruded Pipes Containing a Water-Based Binder

Funtai oyobi fummatsu yakin, 2001

Research paper thumbnail of Special Invited Talk : Fabrication of Bulk Thermoelectric Materials by Powder Extrusion Techniques

Research paper thumbnail of Fabrication and Thermoelectric Properties of Cu-doped Bi-Te-Se Bulk Materials

Funtai oyobi fummatsu yakin, 2016

Research paper thumbnail of Optimization of selective laser melting parameters and influence of post heat treatment on microstructure and mechanical properties of maraging steel

Materials & Design, 2018

The influences of various process parameters on densification behavior, surface morphology, micro... more The influences of various process parameters on densification behavior, surface morphology, microstructure, and mechanical properties of selective laser melted (SLMed) maraging steel have been investigated. A process map for the SLM of maraging steel has been constructed. There exists a relatively large processing window, where sound products with relatively high relative density and good surface quality can be obtained. As-built specimens contained martensite matrix with trace amount of austenite phase. The quantity of austenite phase increased during aging treatment due to reversion of martensite to austenite. Solution treatment/aging resulted in elimination of the austenite phase and formation of intermetallic precipitates in the martensite matrix. The as-built and aged specimens exhibited almost the same average grain size, while solution treatment/aging resulted in grain growth of the martensite matrix and a significant change in grain orientation. The results indicated that the SLMed specimens with the building direction parallel to the loading direction had much lower elongation than those with the building direction perpendicular to the loading direction. The maximum tensile strength and hardness obtained were 2033 MPa and 618HV respectively, after solution treatment at 820 0 C for 1 hour and aging at 460 0 C for 5 hours.

Research paper thumbnail of Microstructure and mechanical properties of in situ synthesized alumina/Ba-β-alumina/zirconia composites

Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, Feb 1, 2004

ABSTRACT

Research paper thumbnail of Interfacial reaction behavior and thermal stability of barium zirconate-coated alumina fiber/alumina matrix composites

Journal of the European Ceramic Society, 2008

ABSTRACT A barium zirconate (BaZrO3) coating was incorporated onto surfaces of alumina fibers, an... more ABSTRACT A barium zirconate (BaZrO3) coating was incorporated onto surfaces of alumina fibers, and the coated alumina fiber/alumina matrix composites were prepared by hot pressing. The interfacial reactions between BaZrO3 coating and Al2O3 fiber/matrix during the consolidation resulted in formation of ZrO2 and Ba–β-Al2O3, one of nonstoichiometric hexaluminate compounds. The diffusion of Ba cations dominates the reaction process between BaZrO3 coating and Al2O3 fiber/matrix. The Ba–β-Al2O3 phase exhibited an elongated morphology due to preferred orientational growth through directional diffusion and mass transport of Ba along the basal plane. The Young's modulus and hardness of the Ba–β-Al2O3 phase were measured by nanoindentation technique to be 250 GPa and 20 GPa, respectively. The BaZrO3-coated Al2O3 fiber/Al2O3 matrix composites showed good microstructural stability during thermal exposure up to 1400 °C.

Research paper thumbnail of Fabrication of aluminum–magnesium clad composites by continuous extrusion

Materials Science and Engineering: A, 2021

Abstract Poor corrosion resistance of Mg alloys extremely limits their industrial applications. A... more Abstract Poor corrosion resistance of Mg alloys extremely limits their industrial applications. Al/Mg clad composites using Al alloy as a protective layer are expected to be an effective approach to combine good corrosion resistance and high specific strength. In this study, novel Al clad Mg composites were developed by continuously extruding 6063 Al alloy tube and AZ31 Mg alloy rod with and without preheating of Mg alloy. The Al/Mg interfacial diffusion, microstructure, texture, and flexural properties of the continuously extruded composites were investigated experimentally. The extruded composites exhibited good metallurgical bonding between Al shell and Mg core even without preheating of Mg alloy, and their fine-grained microstructure contributes to a significant enhancement in ultimate flexural strength (UFS) to 452 MPa. Preheating of Mg alloy caused complete dynamic recrystallization (DRX) of both Al shell and Mg core and modified (0001) texture of the Mg alloy, which leads to a significant improvement in the bendability of the Al/Mg composite.

Research paper thumbnail of 1A41 Study of kinematics evaluation method for total knee arthroplasty

The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME, 2015

Research paper thumbnail of Determination of True Stress–Strain Curves of Sheet Metals in Post-Uniform Elongation Range

MATERIALS TRANSACTIONS, 2009

A novel approach to determination of the true stress-strain relation in a post-uniform elongation... more A novel approach to determination of the true stress-strain relation in a post-uniform elongation range by finite element modeling has been proposed, on the basis of the variation of strain-hardening exponent (n) with strain during uniaxial tensile tests. The strain dependence of n-value can be expressed by a linear or simple quadratic function. The proposed method has been applied to several sheet metals with large differences in strain-hardening behavior. The finite element analytical results, obtained by using constitutive equations derived from a variation of n-value with strain, are in good agreement with the measured load-elongation curves. As the number of parameters is sufficient by two at the most, the optimization by an inverse analysis becomes very easy. It has been verified that the proposed method is effective to estimate the stress-strain curves of sheet metals in the post-uniform elongation range.

Research paper thumbnail of Processing and Microstructure of an All-Oxide Ceramic Composite

Materials Science Forum, 2005

An all-oxide composite consisting of alumina fiber, alumina matrix, and barium zirconate interpha... more An all-oxide composite consisting of alumina fiber, alumina matrix, and barium zirconate interphase has been investigated. The barium zirconate interphase was applied on alumina fibers through coating via a sol-gel route. The incorporation of the coatings did not significantly influence the densification behavior of the composite under hot-pressing conditions. During the processing of the composite, the barium zirconate reacted in situ with alumina fiber and alumina matrix to form Ba-β-alumina platelets with an elongated morphology, which is propitious for crack deflection and thus toughness enhancement. The results reveal that it is possible to reduce fiber strength degradation by controlling the coating and densification processes.

Research paper thumbnail of Characterization of interfacial reaction products in alumina fiber/barium zirconate coating/alumina matrix composite

Materials Characterization, 2002

Barium zirconate (BaZrO 3) is a candidate material for interface engineering of alumina fiber/alu... more Barium zirconate (BaZrO 3) is a candidate material for interface engineering of alumina fiber/alumina matrix composites. Al 2 O 3 and BaZrO 3 react at high temperatures to form a series of reaction products. The objective of this work was to characterize these reaction products and to investigate their effect on crack propagation. BaZrO 3 coating was applied on Al 2 O 3 fibers via a sol-gel route. The characterization was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The reaction products between BaZrO 3 coating and Al 2 O 3 (fibers and/or matrix) included ZrO 2 , barium monoaluminate (BaOÁAl 2 O 3) and Ba b-Al 2 O 3 (BaOÁ7.3Al 2 O 3). In hot-pressed composites, barium aluminate was mainly present in the form of Ba b-Al 2 O 3. The Ba b-Al 2 O 3 is known to have a layer-type structure, which is likely to be propitious for crack deflection. The interfacial reactions are diffusion-controlled solid-state processes, mainly depending on the diffusion of Ba cations. The Ba b-Al 2 O 3 phase can form either through direct reaction between the BaZrO 3 coating and Al 2 O 3 or through indirect reaction between a BaOÁAl 2 O 3 intermediate phase and Al 2 O 3. The BaZrO 3 coating and the reaction products between the coating and fiber/matrix provide multiple weak interfaces, which are likely to result in crack deflection and thus toughness enhancement in an all oxide composite.

Research paper thumbnail of Characterization of interfacial reaction products in alumina fiber/barium zirconate coating/alumina matrix composite

Materials Characterization, 2002

Barium zirconate (BaZrO 3) is a candidate material for interface engineering of alumina fiber/alu... more Barium zirconate (BaZrO 3) is a candidate material for interface engineering of alumina fiber/alumina matrix composites. Al 2 O 3 and BaZrO 3 react at high temperatures to form a series of reaction products. The objective of this work was to characterize these reaction products and to investigate their effect on crack propagation. BaZrO 3 coating was applied on Al 2 O 3 fibers via a sol-gel route. The characterization was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The reaction products between BaZrO 3 coating and Al 2 O 3 (fibers and/or matrix) included ZrO 2 , barium monoaluminate (BaOÁAl 2 O 3) and Ba b-Al 2 O 3 (BaOÁ7.3Al 2 O 3). In hot-pressed composites, barium aluminate was mainly present in the form of Ba b-Al 2 O 3. The Ba b-Al 2 O 3 is known to have a layer-type structure, which is likely to be propitious for crack deflection. The interfacial reactions are diffusion-controlled solid-state processes, mainly depending on the diffusion of Ba cations. The Ba b-Al 2 O 3 phase can form either through direct reaction between the BaZrO 3 coating and Al 2 O 3 or through indirect reaction between a BaOÁAl 2 O 3 intermediate phase and Al 2 O 3. The BaZrO 3 coating and the reaction products between the coating and fiber/matrix provide multiple weak interfaces, which are likely to result in crack deflection and thus toughness enhancement in an all oxide composite.

Research paper thumbnail of Microstructural evolution of reactive-sintered aluminum matrix composites

Composites Science and Technology, 2008

... a Department of Materials Science and Engineering, School of Engineering, Tohoku University, ... more ... a Department of Materials Science and Engineering, School of Engineering, Tohoku University, Aoba-yama 6-6-02, Aoba-ku, Sendai 980-8579, Japan. b Department of Mechanical Systems Engineering, Faculty of Engineering ...

Research paper thumbnail of Validation of 3-dimensional postoperative evaluation technique for Total Knee Arthroplasty

Journal of Japan Society of Computer Aided Surgery

Several surgical assistance systems for total knee arthroplasty(TKA)have been applied to enhance ... more Several surgical assistance systems for total knee arthroplasty(TKA)have been applied to enhance the surgical precision. The accuracy of these surgical assistance systems has been evaluated with regards to the implant setting posture by 2-dimensional X-ray images. It was found that these systems were effective in enhancing surgical precision as reported in several publications. On the other hand, some authors reported no significant difference between these systems and conventional operation. When using 2-dimensional X-ray images for evaluation, a wrong knee posture during image acquisition introduces an error. Therefore, we evaluated several 3-dimensional evaluation methods using CT scans. In this study, we adopted three evaluation methods for TKA：1)CT-based preplanning software, 2)3-dimensional matching using a CAD model, and 3)a surgical navigation system. The error of these evaluation methods was less than 2 mm and 2 degrees. In conclusion, 1)it is important to validate the evaluation tool for each implant geometry and／or each evaluation method, 2)a suitable evaluation method should be selected in accordance with the intended use.

Research paper thumbnail of Microstructure, Texture, and Mechanical Properties of Continuously Extruded and Rolled AZ31 Magnesium Alloy Sheets

Journal of Materials Engineering and Performance

Research paper thumbnail of 601 Mechanical Properties of Al-Al_2O_3-TiB_2 Composite Processed by Reactive Sintering and Hot-Rolling

The Proceedings of Autumn Conference of Tohoku Branch

Research paper thumbnail of 603 Formability of Al-Al_2O_3-TiC Composite Processed by Reactive Sintering and Hot Compression

The Proceedings of Autumn Conference of Tohoku Branch

Research paper thumbnail of 613 Plastic Anisotropy of A2024-O and T6 Aluminum Alloys

The Proceedings of Autumn Conference of Tohoku Branch