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ID 25941
file
creator
Mamiya, Hiroshi
Choi, Yong-Bum
Yanagisawa, Osamu
Kuramoto, Hideaki
subject
shape memory alloys
levitation melting
electron theory
oxidation resistance
ternary TiNi
alloy design
high purity
environmentally friendly materials
NDC
Metal and mining engineering
abstract
The addition of Re, Fe and Cr into Ti-50mol%Ni has been carried out to improve the oxidation and mechanical properties. The mono phase consisting of TiNi with the B2 type structure was identified in micro-alloyed materials proposed on the basis of the d-electrons concept. Experimentally TiNi alloys were melted and solidified by the cold crucible levitation method (CCLM). The TiNi-(Cr, Fe, Re) alloys with high purity and without contamination from a crucible were prepared, and the homogeneous microstructure was achieved by the diffusion mixing effect of CCLM even in the as-cast alloys which contained Re and Cr with higher melting temperatures and different specific gravities. All alloys were caused the transformation from austenite to martensite phases below or above room temperature. The some alloys had the ability of shape memory even at room temperature. Ternary alloys showed higher flow stress level compared with the binary TiNi alloy. On the other hand, the oxidation at 1273K was promoted by the formation of titanium oxides (TiO2) on the alloy surfaces. The oxidation resistance was improved by the formation of the continuously Cr2O3 film in TiNi-Cr alloys. The alloying effects by ternary elements (Re, Fe, Cr) in the intermetallic TiNi as well as metallic materials were explained well using two parameters used in the d-electrons concept.
journal title
International Journal of Cast Metals Research
volume
Volume 21
issue
Issue 1-4
start page
156
end page
161
date of issued
2008-08
publisher
Maney Publishing
issn
1364-0461
ncid
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
author
relation url
department
Graduate School of Engineering