1999 Fiscal Year Final Research Report Summary
Research on Development of Shape Memory Elements by Powder Injection Molding Process
| Project/Area Number |
09650122
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Materials/Mechanics of materials
|
|---|
| Research Institution | Kinki University |
|---|
Principal Investigator |
KYOGOKU Hideki Kinki University, School of Engineering, Professor, 工学部, 教授 (10258056)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
KOMATSU Shinichiro Kinki University, School of Engineering, Professor, 工学部, 教授 (70140316)
|
|---|
| Project Period (FY) |
1997 – 1999
|
| Keywords | Shape memory alloy / Ti-Ni alloy / Powder injection molding / Sintering / Density / Mechanical properties / Recovery stress / Recovery strain |
|---|
| Research Abstract |
The fabrication of Ti-Ni shape memory alloy by elemental powders was attempted by using both the powder injection molding and the spark-plasma sintering method in order to develop the shape memory elements. The relations between the fabrication conditions and the microstructures, mechanical properties and thermomechanical properties of the sintered compacts were investigated systematically. The results obtained are as follows ;
(1) In case of the powder injection molding method, the relative density of the sintered compacts was about 67%. Therefore, the tensile properties of the sintered compact were fairly less than those of the wrought materials ; the tensile strength was about 110 MPa and the elongation was 1.5%. But the sintered compacts showed apparently the shape memory property in the recovery stress test.
(2) In case of the spark-plasma sintering method, the appropriate sintering temperature and holding time, which can produce the high-relative density sintered compacts of about
… More
98%, were found. The appropriate heat-treatment conditions making the microstructure of sintered compacts more homogeneous was also found. The sintered compacts having the superior tensile properties could be successfully fabricated by the heat treatment ; the tensile strength was around 800 MPa and the elongation was over 7%. This result is one of the highest tensile properties that have been already obtained by the powder metallurgy. The sintered compacts showed the superior recovery stress ; the recovery stress after loading of 2% pre-strain was around 230 MPa after first cycle and became around 300 MPa after 15th cycle.
Thus, we could investigate the basic shape memory characteristics of the sintered compacts enough to utilize the shape memory alloy for fabricating the elements. After this, the mechanical properties and shape memory characteristics may be improved by more detailed examination of the fabrication conditions and by structure homogenization by using alloy powder instead of elemental powders. Less
|
