Japanese Page
Welcome
to High Functional Materials Laboratory
Department
of Materials Science and Engineering
Shibaura
Institute of Technology
Shibaura
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
Master's
degree
1981
Doctor's
degree
Doctor
of Engineering
1984 Department of Materials Science, The
Job
career
1984 Research Scientist, Fundamental Research
Laboratory I, Nippon Steel Corporation
1989 Senior Research Scientist, Superconductivity
Research Laboratory,
1994 Division Director, Superconductivity Research
Laboratory,
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,
1997
- 2001 Visiting Professor,
2001
- Visiting Professor,
2003
- Special Research Scientist,
Superconductivity Research Laboratory
Current
positions
Asian
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
Director,
Materials Research Society of
Advisor,
Iwate prefecture government
Co-chairman,
5th PASREG Workshop
Awards
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
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・Department of
Materials Science and Engineering
Prof. Dr. Takao Utsunomiya, Faculty of
Engineering・Department of
Mechanical Engineering
Prof. Dr. Tsutomu Ezumi, Faculty of Engineering・Department 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
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’s 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