Graduate School of Engineering
Department of Metallurgy

Materials Forming and Structural Control
Forming Process Technology (Prof. Oikawa)

Research Topics

Basic Research on Rolling of Steels and Nonferrous Metals

With the help of basic understanding on deformation mechanism of materials from both aspects of experiment and analysis, it becomes possible to form new materials and develop new fabrication processes easily. For example, when high-strength steels are formed by conventional techniques, there exist some problems such as poor accuracy and formation of defects. For rolled sheets with adequate surface roughness, lubricants can be involved in concave of the surface so as to maintain the lubrication between the sheet and die during press forming. However, it is difficult to provide appropriate roughness for high-strength materials. By means of basic experiments simulating rolling or press forming and finite element analysis, the formation mechanism of surface under rolling deformation can be understood. Furthermore, it is possible to obtain the information on the most suitable surface roughness and to develop the optimum process to form this surface roughness by estimating the friction state during press forming.

Secondary Plastic Working of Materials

Concerning the forming of long products, it is better to use roll forming other than press forming. However, the conditions to form high-strength materials with high accuracy remain unclear. Currently, the basic experiments and analyses on roll forming of high-tensile strength steel sheets and forging of Al alloys are under investigation.

Fabrication of High-Performance Materials by Powder Processing

Various advanced functional materials and composite materials are synthesized or fabricated by powder processing techniques. The research work is focused on (i) control of chemical reactions, microstructural evolution, and textural development during powder processing and (ii) relationships among powder characteristics, processing parameters, microstructures and mechanical, physical or thermoelectric properties. Current research interests include:

  1. Fabrication of thermoelectric materials such as Bi2Te3, Zn4Sb3, and CoSb3 systems
  2. Processing and toughening of all-oxide ceramic-matrix composites
  3. Coextrusion of ceramic composites for solid oxide fuel cells
  4. In-situ synthesis and characterization of metal-matrix and intermetallic-matrix composites
  5. Preparation of high-performance clad steel pipes by powder multi-billet extrusion technique
Fig. 1:HRTEM image of hot-extruded Bi2Te3 thermoelectric compound

Fig. 1:
MHRTEM image of hot-extruded Bi2Te3 thermoelectric compound

Fig. 2:SEM microstructure of an in-situ synthesized alumina matrix composite

Fig. 2:
SEM microstructure of an in-situ synthesized alumina matrix composite