Welcome to High Functional Materials Laboratory
Department of Materials Science and Engineering
Shibaura Institute of Technology
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
High temperature deformation
5. Joining of Materials
Friction stir welding
Brazing of superconducting materials
(please see Center for Interconnecting Science and Technology)
1979 Department of Materials Science. The
Doctor of Engineering
1984 Department of Materials Science, The
1984 Research Scientist, Fundamental Research Laboratory I, Nippon Steel Corporation
1989 Senior Research Scientist, Superconductivity
1994 Division Director, Superconductivity Research
2003 Professor, Department of Materials Science and Engineering, Shibaura Institute of Technology
2004 Director, Center for Interconnecting Science and Technology
- 1997 Visiting Professor,
- 2001 Visiting Professor,
- Visiting Professor,
2003 - Special Research Scientist, Superconductivity Research Laboratory
editor, Superconductor Science and Technology (IOP)
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
Materials Research Society of
Advisor, Iwate prefecture government
5th PASREG Workshop
1972 The second prize in mathematics contest in
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
1999 Chartered Physicist of IOP
2000 Superconductivity Science and Technology Award
2003 Special PASREG Award
"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)
"New age of superconductivity" (in Japanese)
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
Prof. Dr. Masato Murakami
Department of Materials Science and Engineering
Members of the Center:
A. Prof. Takeo Yokota, Faculty of EngineeringEDepartment of Materials Science and Engineering
Prof. Dr. Takao Utsunomiya, Faculty of EngineeringEDepartment of Mechanical Engineering
Prof. Dr. Tsutomu Ezumi, Faculty of EngineeringEDepartment 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
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
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 yearfs 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).
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
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