DEVELOPMENT STUDY OF BCC-TYPE LIGHT SUPPERALLOY WITH HIGH RESISTANCE TO CORROSION AND ENVIROMENT OXIDATION

1999 Fiscal Year Final Research Report Summary

• Project/Area Number: 10555234
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 展開研究
• Research Field: Structural/Functional materials
• Research Institution: MIYAGI NATIONAL COLLEGE OF TECHNOLOGY
• Principal Investigator: YOSHIDA Mitsuhiko MIYAGI NATIONAL COLLEGE OF TECHNOLOGY, MATERIALS SCIENCE AND ENGINEERING, PROFESSOR, 材料工学科, 教授 (40042254)
• Co-Investigator(Kenkyū-buntansha): KITASGAWA Akio MIYAGI NATIONAL COLLEGE OF TECHNOLOGY, MATERIALS SCIENCE AND ENGINEERING, ASSISTANT PROFESSOR, 材料工学科, 助教授 (90270199) ; KUMAGAI Koichi MIYAGI NATIONAL COLLEGE OF TECHNOLOGY, MATERIALS SCIENCE AND ENGINEERING, RECTURER, 材料工学科, 講師 (00205163) ; TAKASUGI Takayuki UNIVERSITY OF OSAKA PREFECTURE, PROFESSOR, 材料工学科, 教授 (20108567)
• Project Period (FY): 1998 – 1999
• Keywords: intermeallic compound / high-temperature / CoTi / Co_2AlTi / duplex phase / interfacial dislocation

Research Abstract

The microstuructre and morphology of interfacial dislocation between CoTi and Co_2AlTi intermetallic are investigated by X-ray diffraction and transmission electron microscopy. And also, high temperature mechanical properties are investigated by tensile and compression test. The B2 type CoTi single phase polycrystal alloy exhibits the anomalous positive temperature dependence of the tensile yield strength as same as the result obtained by compression test. However, the values of tensile yield stress were lower than those of the compression test in whole test temperature. The fracture mode of all tested specimens showed cleavage and brittle fracture. It was not observed the precipitation of Co_2AlTi in CoTi alloy doped by 2at.%Al. And the acicular precipitation of Co_2AlTi with interfacial dislocations was observed in the specimen added over 3at.%Al.