1999 Fiscal Year Final Research Report Summary
Evaluation of Transformation Strain of Displacive- type and Diffusional- Type Transformations by Means of Precise Measurements of Surface Relieves
| Project/Area Number |
10305044
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (A)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Physical properties of metals
|
|---|
| Research Institution | HOKKAIDO UNIVERSITY |
|---|
Principal Investigator |
MARUKAWA Kenzaburo Grad. School of Eng., Hokkaido Univ., Pro., 大学院・工学研究科, 教授 (20001191)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
TAKAMA Toshihiko Grad. School of Eng., Hokkaido Univ., Asso. Pro., 大学院・工学研究科, 助教授 (40001309)
TAKEZAWA Kazuyoshi Grad. School of Eng., Hokkaido Univ., Inst., 大学院・工学研究科, 助手 (80001311)
|
|---|
| Project Period (FY) |
1998 – 1999
|
| Keywords | phase transformation / martensite / bainite / Cu alloy / atomic force microscope / electron back scatter pattern |
|---|
| Research Abstract |
The purpose of this research is to evaluate the transformation strain of various transformation products . The materials used are metals and alloys . Generally, phase transformations are divided into two categories, displacive type and diffusional type. In the displacive type transformation, atoms are displaced in a cooperative manner during the lattice transformation. In the diffusional type transformation, it has been broadly believed that atoms move individually to create new atomic arrangements . The displacive type transformation necessarily accompanies a transformation strain, while the diffusional type doesn't. There are, however, a few reports that some surface relieves are associated with the latter transformation. In this research, a special attention was paid to examine whether a transformation strain is associated with the bainitic (diffusional) transformation in Cu alloys, or not.
An atomic force microscope was used to image profiles of surface relieves associated with bainites. Electron back scatter patterns was used to obtain the crystallographic orientation of bainite, which was also necessary in order to determine the transformation strain. It has been found that the transformation strain associated with bainites is almost the same as that of martensites . From this result, it has been concluded that the bainitic transformation must contain cooperative atomic movements as the transformation mechanism.
|
