In our laboratory, we are conducting research on bonding process among material working processes.
The bonding process is a basic technology used in all manufacturing processes from electronic components to aerospace equipment.
We research mainly on the following subjects in order to create better-characteristic joints.
1. Research on material structure at weld
Due to the thermal history of the high temperature bonding process, the material structure of the joint changes and the material properties change accordingly.
Therefore, basic research is performed from the viewpoint of material histology regarding the change in properties of joints of various materials.
Recently, the material properties are greatly influenced by the crystal grains constituting the microstructure and the character distribution of the grain boundaries, so we are trying to analyze and control the joint structure using the automatic crystal orientation analysis system OIM (Orientation Imaging Microscopy).
2. Research on material physical chemistry of bonding process
In many joining methods, very high temperatures are used, and the joint may suffer from a rapid thermal history and damage the original properties of the material.
Therefore, the interaction between the solid, gas and liquid in the joining process is analyzed from the viewpoint of material physics, and knowledge about various reactions in the joining process and the contamination of the joint is obtained. Use for improvement and development.
3. Research on weld and surface reforming by high energy beam
The method of bonding and surface modification of materials by irradiating a high-density energy beam such as an electron beam or a laser beam is characterized by a high-speed heating / cooling cycle in a narrow area. Although it shows the possibility of creating material properties, which are superior to ordinary melt bonding methods, there are many unknown points.
Therefore, systematically investigate the various characteristics of the joint and the surface modified portion to further improve the performance.
4. Research on bonding under special environment
As ocean development progresses and the use of outer space is studied, it is necessary to construct structures in various special environments. However, there are many problems in the bonding process and there are few basic data.
Therefore, we will accumulate basic data on the bonding process in special environments such as underwater high-pressure atmosphere on the seabed and reduced-pressure microgravity atmosphere in space, and examine the conditions for obtaining a sound joint efficiently.
5. Research on various bonding processes
Diffusion bonding, brazing, pressure welding, etc. are less affected by heat than melt bonding, and can be used to bond materials that are difficult to melt and dissimilar, as degradation of material properties due to the bonding process can be kept relatively small.
However, there are problems such as the soundness of the joint and the reaction phase and segregation at the joint interface, and unclear points remain in the joining mechanism.
Therefore, we will study how to efficiently obtain high-quality joints while clarifying the joining mechanism of various joining processes.