|1.Research Institution||Yokohama National University|
|2.Research Area||Physical and Engineering Sciences|
|3.Research Field||Next‐generation Process Technologies|
|4.Term of Project||FY 1997 〜 FY 2001|
|6.Title of Project||Mesoscopic Process for the Development of Structural Ecomaterials|
|Name||Institution,Department||Title of Position|
|Akira, Azushima||Yokohama National University, Graduate School of Engineering||Professor|
|Names||Institution,Department||Title of Position|
|Katsutoshi, Komeya||Yokohama National University, Graduate School of Environment and Information Sciences||Professor|
|Hiroshi, Fukutomi||Yokohama National University, Graduate School of Engineering||Professor|
9.Summary of Research Results
Materials technology has been developed to realize better performance and higher quality.
However, recent social circumstances brought about a new mission to materials science, namely
harmony with our environment. In the field of structural materials, this clearly requests us to find
a new process which produces materials, so called ecomaterials with high strength, in order to reduce
energy loss. In this research project, materials with high strength are developed for structural
ecomaterials by refining the grain size, the powder grain and so on. Groups of such materials are as
follows: (1) Metal and alloys with high strength at low temperature by side extrusion process under
hydrostatic pressure. (2) Ceramics with high strength and high reliability at high temperature by
processes to control the reaction rate and microstructure in the fabrication of non-oxide ceramics.
(3) Intermetallics with high strength at high temperature by processes to control the anisotropic
microstructure of TiAl intermetallic compound. (4) The materials with low friction and low wear are
produced by using surface treatment processes.
In the side extrusion process under hydrostatic pressure, the processes were repeated up to 10 passes using the carbon steels. For an example, for the ultra low carbon steel, an ultrafine grained steel with a tensile strength of over 1000MPa was developed with a grain size of 0.5μm x 0.2μm after 10 passes. The cold formability of the carbon steels was very good, and by the heat treatment, the uniform elongation became longer. In the process to control the reaction rate and microstructure in the fabrication of non-oxide ceramics, an unusual morphology of hollow balls of 200 to 500nm with a great deal of nano α-sialon particles of around 10 to 30nm was discovered. By using the nano α-sialon particles, the α-sialon with higher strength was developed. In the processes to control the anisotropic microstructure of TiAl intermetallic compound, TiAl sheet with high oriented lamella was developed and the creep strength increased.
(1)Environment、(2)Structural Ecomaterials、(3)Inorganic materials