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5th PASREG 2005
Publication

Welcome to High Functional Materials Laboratory

Department of Materials Science and Engineering

Shibaura Institute of Technology

Shibaura 3-9-14, Minato-ku, Tokyo 108-8548 Japan

 

Professor

Masato Murakami

e-mail masatomu@sic.shibaura-it.ac.jp

 

 

Research Interests

1. Superconducting Materials

Flux pinning properties

Processing of high temperature superconductors

Magnetic properties of bulk superconductors

Applications of high temperature superconductors

 

2. Magnetic Materials

Interaction of ferromagnetic spheres

Applications of Fe-Nd-B magnets

 

3. Shape Memory Alloys

Fe-Mn-Si shape memory alloys

Applications of Fe-Mn-Si shape memory alloys

 

4. Mechanical Properties of Metals

Super-plasticity

High temperature deformation

 

5. Joining of Materials

Friction stir welding

Brazing of superconducting materials

(please see Center for Interconnecting Science and Technology)

 

 

 

Academic degrees

Bachelor's degree

1979  Department of Materials Science. The University of Tokyo

Master's degree

1981  Graduate School, Department of Materials Science, The University of Tokyo

Doctor's degree

Doctor of Engineering

1984  Department of Materials Science, The University of Tokyo

 

Job career

1984  Research Scientist, Fundamental Research Laboratory I, Nippon Steel Corporation

1989  Senior Research Scientist, Superconductivity Research Laboratory, International Superconductivity Technology Center

1994  Division Director, Superconductivity Research Laboratory, International Superconductivity Technology Center

2003  Professor, Department of Materials Science and Engineering, Shibaura Institute of Technology

2004  Director, Center for Interconnecting Science and Technology

 

Academic positions

1995 - 1997  Visiting Professor, Nagoya University

1997 - 2001  Visiting Professor, Iwate University

2001 -       Visiting Professor, Tokyo University of Marine Science and Technology

2003 -       Special Research Scientist, Superconductivity Research Laboratory

 

Current positions

Asian editor, Superconductor Science and Technology (IOP) UK

Editor, Ceramics International

Editor, Journal of Rare Earths

Editor, Korean Journal of Cryogenic Society

Editor, Japanese Journal of Cryogenic Society

Co-convenor, Working group 10, IEC-TC90

Chairman, International Pasreg Board

Director, Materials Research Society of Japan

Advisor, Iwate prefecture government

Co-chairman, 5th PASREG Workshop October 23 - 25, 2005 held at Tokyo University of Marine Science and Technology

 

Awards

1972  The second prize in mathematics contest in California state

1990  President Award of Nippon Steel Corporation

1990  Director's Award of Superconductivity Research Laboratory

1991  Nikkei BP prize

1992  World Congress Superconductivity Award of Excellence

1996  Culture Prize of Iwate Daily News

1998  Development Award of Nippon Materials Society

1999  Chartered Physicist of IOP

2000  Superconductivity Science and Technology Award

2003  Special PASREG Award

 

Authored books

"Melt processed high temperature superconductors", World Scientific, 1991

"Now I understand superconductivity" (in Japanese)

Kodan-sha blue backs, 1999

"Materials science in high temperature superconductivity" (in Japanese)

Uchida-rokakuho, 1999

"New age of superconductivity" (in Japanese)

Kogyo-chosa-kai, 2000

Mathematic series (in Japanese)

"Introduction to Imaginary numbers", Kaimei-sha, 2000

"Introduction to Calculus", Kaimei-sha, 2001

"Introduction to Linear Algebra", Kaimei-sha, 2001

"Introduction to Fourier analysis", Kaimei-sha, 2001

"Introduction to Complex Functions", Kaimei-sha, 2002

"Introduction to Vector analysis", Kaimei-sha, 2003

"Introduction to Statistics", Kaimei-sha, 2002

"Introduction to Probability", Kaimei-sha, 2003

"Introduction to Regression analysis", Kaimei-sha, 2004

Physics series (in Japanese)

"Introduction to thermodynamics", Kaimei-sya, 2004.

 

Center for Interconnecting Science and Technology

Shibaura Institute of Technology

 

Director

Prof. Dr. Masato Murakami

Department of Materials Science and Engineering

 

Members of the Center:

A. Prof. Takeo Yokota, Faculty of EngineeringEDepartment of Materials Science and Engineering

Prof. Dr. Takao Utsunomiya, Faculty of EngineeringEDepartment of Mechanical Engineering

Prof. Dr. Tsutomu Ezumi,  Faculty of EngineeringEDepartment of Mechanical Engineering

 

 

1.  Research Topics

The main research topic of the center is the interconnection or joining of various materials.  In most practical applications of industrial materials, they are not used as single pieces but as an integrated system that consists of many components.  Hence, interconnection or joining of the materials is indispensable. 

   In this research center, we focus on four novel joining techniques: friction stir welding, microsoldering, room temperature joining, and superconducting welding for three functional materials: superplastic aluminum alloys, lead-free solder, and high temperature superconducting materials. 

   Joining of materials is thus a really interdisciplinary research area and a collaborative joint study among researchers from different areas is necessary.  The foundation of the center for interconnecting science and technology is thus timely and will be useful for gathering information in this field and promoting research activities.  The final target of the project is the developments of the joining techniques that can be used for engineering applications in various fields including superconducting and semiconducting technologies.

 

2. The role and the field of research of each member in the center

Masahisa Otsuka: Supervising the whole project and research on lead-free soldering materials and suitable joining conditions for the solder with the emphasis placed on micro-soldering for electronic devices.

Masato Murakami: Developments for joining techniques for high temperature superconducting materials and the characterization of superconducting properties of the joints.  The focus is first placed on the welding of large grain RE-Ba-Cu-O superconducting materials, but later the joining of other superconducting materials like superconducting wires will also be studied.

Takeo Yokota: Research on a friction stir welding (FSW) method and the microstructural and mechanical characterization of the joint made by FSW.

Takao Utsunomiya: Characterization and in-situ detection of defect structures in the joint between metal and metal composites.

Tsutomu Esumi: Non-destructive evaluation of the joint between different materials.

 

3. Research Achievements

3. 1.  Friction stir welding 

When conventional fusion welding is employed for die-cast alloys, the mechanical reliability of the joint is largely depressed due to the formation of pores.  We confirmed that the joints of ADC12 aluminum alloys fabricated by the friction stir welding method are defect-free and exhibit good mechanical properties that are almost comparable to those of the mother alloys.  In addition, we also confirmed that the FSW will be suitable for obtaining good joints for AZ61 and AZ91 magnesium alloys.

 

3. 2.  Micro-soldering

     The lifetime of electronic devices is often governed by the mechanical reliability at the soldered joints.  Thus it is important to seek for a simulation method to reflect the environmental conditions for soldering micro electronic devices.  For this purpose, we designed a special mold that allows us to reproduce the conditions under which soldering of micro electronics devices is performed in factories.  We then tested miniature samples of Sn-3Ag-0.5Au alloy about 1mm in diameter.  It was found that microstructure of the soldered micro devices is completely different from that of the sample prepared by conventional metallurgical processes.  Hence we renew the process to simulate micro-soldered electronic devices.  These results are so important that Japan industrial standards organized by METI will employ our methods as standards in the future.

 

3. 3.  Room temperature joining

     Room temperature joining is a unique method to weld two different materials at room temperature without glue.  For this process to occur, highly purified surfaces are necessary.  We studied the joining of two different materials with completely different structure and physical properties such as metal and ceramics.  Though it is still preliminary, good joints were obtained in Al-Si and Al-Al2O3.  We believe that this yearfs success is promising and may provide an effective tool for joining different materials especially in the field of the system integration of future electronics devices.

 

3. 4.  Superconductor joining

     Bulk high temperature superconducting RE-Ba-Cu-O materials are attractive for various engineering applications such as magnetic levitation devices and strong quasi-permanent magnets.  For these applications, it is desirable that the samples have large dimensions.   These materials must be grown into single grain in order to exhibit good performances.  Hence the bulk superconductors are produced by melt processing using a seeding technique.  It is however difficult to grow large grain crystals.  The joining of small bulk RE-Ba-Cu-O materials is therefore very critical for the production of large bulk superconductors.  We employed melt-growth-based joining in that epitaxial growth from the joined surfaces is used.  Proper selection of joining reagent and the control of the crystal orientation of joined surfaces enabled us to fabricate strongly coupled superconducting joint.

 

4. Research Scheme in the future

  We will continue the research on the friction stir welding of different materials with the aim of seeking for the welding method of high functional materials together with the joining of the materials with different chemical and physical properties. 

As for micro-soldering, since we found that the heat cycle and microstructure for soldered micro-devices were different from those obtained in conventional metallurgical processes, we will try to reproduce the soldering conditions for micro-devices and further study how microstructure is controlled with the aim of seeding for suitable welding conditions for system integration of microchips.

Room temperature joining is a unique and an attractive method for contacting two different materials.  The idea is brand new and has still unknown parameters, although we could show that combinations of Al/Si and Al/Al2O3 materials could be joined with this method.  The key to successful joining is the preparation of highly pure surfaces.  We will continue to brush up this method and try to join other combinations of materials.  The target of this project is the system integration of micro electronic devices for the next generation semiconducting devices.

    Superconducting joining is critical for the realization of practical engineering applications of bulk high temperature RE-Ba-Cu-O materials.  We found that a proper selection of joining reagent and a control of crystal orientation along (110) planes of joined blocks lead to strongly coupled joints.   The technique was however only applied to small specimens.  The benefits of the superconducting welding are for large samples.  We therefore try to employ a newly developed welding method for joining large massive blocks.  The joining of superconducting wires is also a very critical issue for the realization of persistent current mode operation of a superconducting solenoid.  Thus we will join the superconducting wires. 

    In addition to the joining methods described above, we will study on a spark plasma sintering (SPS) method, and the joining of metal pipes using a shape memory alloy (SMA).

 

5. Others

     In order to promote the research project in multi-interdisciplinary nature, we are conducting collaboration with the members outside the university.  Prof. Tadatomo Suga of Tokyo University is an expert in the field of room temperature joining.  In fact, the idea was first proposed by Prof. Suga, who is also a member of the center and is vigorously involved in this research topic.  Dr. Yohsiharu Kariya of National Institute of Materials Science is also a member of the center and is working on micro-soldering with the aim of integrating micro electronics systems using lead-free solders. 

 

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