2002 Fiscal Year Final Research Report Summary
Research on Fabrication of Shape Memory Elements using MA Functional Powder and Their Operation Methods
| Project/Area Number |
12650103
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Materials/Mechanics of materials
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| Research Institution | Kinki University |
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Principal Investigator |
KOMATSU Shinichiro Kinki University, Mechanical Engineering, Professor, 工学部, 教授 (70140316)
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| Co-Investigator(Kenkyū-buntansha) |
KYOGOKU Hideki Kinki University, Mechanical Engineering, Professor, 工学部, 教授 (10258056)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Shape memory alloy / Ti-Ni-Cu alloy / Mechanical alloying / Spark plasma sintering / Shape memory characteristics / Superelasticity / Thermo-mechanical properties / Cyclic deformation properties |
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| Research Abstract |
The purpose of this research is to investigate the applicability of TiNi shape memory alloy fabricated using mechanically alloyed powders to the shape memory elements and their operation methods. Ti-Ni powders were fabricated by means of mechanical alloying (MA) and improved by additions of Cu and B. The shape memory characteristics, thermo-mechanical properties, such as recovery stress and recovery strain, and cyclic deformation properties of the alloys fabricated by spark-plasma sintering were systematically investigated. The results obtained are as follows:
(1)The shape memory alloys were fabricated using the Ti-Ni-Cu powder mixed by ball-milling and their mechanical and shape memory properties were examined. In case of 20at%Cu in Ti-Ni-Cu alloys, the mechanical properties of the alloys were comparable to those of the wrought materials; the tensile strength was about 500 MPa and the elongation was around 7%. The alloy showed superelasticity in the isothermal test, and very low deform
… More
ation resistance and higher practical recovery stress of 250 MPa in the recovery stress test.
(2) The effects of ball to powder weight ratio, milling time and rotational speed on the powder characteristics and the relation between process control agents and contamination were systematically investigated. The appropriate fabrication conditions were found, and the tensile strength of the Ti-Ni alloy of the powder mechanically alloyed with no process control agent at 200 rpm for 18 ks was 800 MPa. Thus, the alloys superior in tensile properties to the alloys of the elemental powders could be successfully fabricated by MA.
(3) We attempted to improve the shape memory characteristics of the Ti-Ni alloy by the ternary addition of Cu and B. The alloys having very high density were obtained by addition of Cu, and the alloys of Cu addition were near 100% in relative density and showed good temperature-response. But the improvement of shape memory characteristics was not enough by addition of B.
Thus, we could improve the shape memory characteristics of the alloys using MA powder and confirm the applicability of the alloys fabricated using MA powders to the shape memory elements. Less
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