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Equal Channel Angular Extrusion (ECAE) was invented in 1977 in the former Soviet Union by Vladimir Segal, for which he obtained an Invention Certificate of the USSR, similar to a patent. Researchers in the Department of Mechanical Engineering have been conducting research on the ECAE process since 1992. Segal, was a research associate in the Laboratory from 1992 to 1995.
ECAE is a new and exciting method of inducing large plastic deformation to materials without changing the size or general shape of the billet. There are some interesting properties that arise from this extrusion process, such as increased material strength, hardness, and many other case dependent features. The extrusion process is carried out at temperatures ranging from 77K to 1500K, depending on the material and desired results. It is accomplished by forcing a billet of material through two intersecting channels of only slightly larger dimensions. The angle can be chosen between 0 and 90 degrees to provide a varied amount of strain. As the billet passes the turn, the material must shear in a fashion unique to this process.
The material will endure dramatic but uniform deformation after the extrusion, and yet the basic size and shape of the billet remains unchanged. The billets can be processed with multiple passes through the dies to further cold work the material. Also, varying the entry orientation of the billet with successive passes can further vary the results. This process holds much promise for the higher material specification demands of tomorrow.
Research has concentrated in two areas: (1) developing theoretical and practical knowledge of the mechanics of ECAE (mathematically modeling, etc.) and (2) investigating the various technological advantages of ECAE. To date, TAMU has found many advantages with ECAE, including a variety of microstructures, as well as equiaxed, laminar, and fibrous textures for many materials. ECAE has also been found to be an excellent method for powder consolidation.
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