2004 Fiscal Year Final Research Report Summary
Formation mechanism of self-organized nanostructured -metallic glass composite
| Project/Area Number |
15510096
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Nanomaterials/Nanobioscience
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
SAIDA Junji Tohoku University, Center for interdisciplinary Research, Associate professor, 学際科学国際高等研究センター, 助教授 (20359540)
|
|---|
| Project Period (FY) |
2003 – 2004
|
| Keywords | metallic glass / nanostructured material / transformation / mechanical properties / local structure / cluster / nano icosahedral quasicrystal |
|---|
| Research Abstract |
(1)The formation pf nanostructured-metallic glass composite has been found in the rapidly quendied Cu-(Zr or Hf)-Ti alloys.
(2)The nanocrystalline particles have a fine grain size of 5 to 10 nm in diameter and are dispersed homogeneously in the glassy matrix.
(3)The nanocrystalline particles have a metastable cubic structure with Cu-rich composition, which are brought us the formation mechanism of the stable Cu-rich clusters in the supercooled liquid state.
(4)The primary transformation process is clarified in both the alloy systems, where another metastable CuZr phase is formed remaining the nanocrystalline cubic phase in the as-quenched state in the Cu-Zr-Ti alloy. However, the glassy and metastable cubic phases are transformed into the Cu8Hf3 phase in the Cu-Hf-Ti alloy.
(5)The high mechanical strength is exhibited in the nanostructured-metallic glass composite in the Cu-Zr-Ti alloy and it is improved in the primary crystallized state. It is due to the formation of two different nanocrystalline phases.
(6)Nano icosahedral quasicrystalline phase formation is found in the primary stage in the Zr65Al7.5Cu27.5 metallic glass, where the icosahedral cluster has a high stability in the supercooled liquid state.
(7)The fracture mechanism of the nano icosahedral quasicrystal dispersed Zr-Pt binary amorphous alloy is investigated. We have found that the fracture takes place in the glassy region among the dispersed icosahedral particles.
(8)In these studies, we can conclude that the nanoscale structure control based on the metallic glasses using the stable duster and/or local structure is very effective on the improvement of mechanical properties as well as is very important on the investigation of fundamental properties such as the formation mechanism and transformation process in the materials.
|
