Abstract
In order to overcome the recrystallization embrittlement of molybdenum, internally nitrided dilute Mo-Ti alloy specimens having a heavily deformed surface microstructure were prepared by a novel three-step internal nitriding process at 1223-1873 K in N2 gas. Grain growth behavior and mechanical properties of nitrided specimens were investigated. Primary nitriding of the present alloys below their recrystallization temperature induced a uniform dispersion of ultrafine Ti-nitride precipitates without causing recrystallization. After secondary and tertiary nitriding, those precipitates grew into rod-like particles with a diameter of about 20 nm and a length of 50-120 nm, maintaining their deformed microstructure due to the pinning effect on grain boundary migration. The depth of the region where the recrystallization of the molybdenum matrix was suppressed was greatly dependent on the secondary nitriding temperature. The recrystallization temperature of the specimen subjected to three-step nitriding was elevated above 1873 K. The yield strength at 298 K obtained from nitrided Mo-0.5 wt% Ti alloy was about 1.6 times as high as that of the recrystallized specimen. Ductile-to-brittle transition temperature of nitrided Mo-0.5 wt% Ti alloy was about 181 K.
| Original language | English |
|---|---|
| Pages (from-to) | 50-56 |
| Number of pages | 7 |
| Journal | Materials Science and Engineering A |
| Volume | 406 |
| Issue number | 1-2 |
| DOIs | |
| Publication status | Published - Oct 15 2005 |
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Keywords
- Dilute Mo-Ti alloys
- Ductile-to-brittle transition temperature
- Multi-step internal nitriding
- Pinning effect
- Recrystallization temperature
- Ti-nitride precipitate
ASJC Scopus subject areas
- Materials Science(all)
Cite this
Preparation of structurally controlled dilute molybdenum-titanium alloys through a novel multi-step internal nitriding technique and their mechanical properties. / Nagae, Masahiro; Takemoto, Yoshito; Yoshio, Tetsuo; Takada, Jun; Hiraoka, Yutaka.
In: Materials Science and Engineering A, Vol. 406, No. 1-2, 15.10.2005, p. 50-56.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Preparation of structurally controlled dilute molybdenum-titanium alloys through a novel multi-step internal nitriding technique and their mechanical properties
AU - Nagae, Masahiro
AU - Takemoto, Yoshito
AU - Yoshio, Tetsuo
AU - Takada, Jun
AU - Hiraoka, Yutaka
PY - 2005/10/15
Y1 - 2005/10/15
N2 - In order to overcome the recrystallization embrittlement of molybdenum, internally nitrided dilute Mo-Ti alloy specimens having a heavily deformed surface microstructure were prepared by a novel three-step internal nitriding process at 1223-1873 K in N2 gas. Grain growth behavior and mechanical properties of nitrided specimens were investigated. Primary nitriding of the present alloys below their recrystallization temperature induced a uniform dispersion of ultrafine Ti-nitride precipitates without causing recrystallization. After secondary and tertiary nitriding, those precipitates grew into rod-like particles with a diameter of about 20 nm and a length of 50-120 nm, maintaining their deformed microstructure due to the pinning effect on grain boundary migration. The depth of the region where the recrystallization of the molybdenum matrix was suppressed was greatly dependent on the secondary nitriding temperature. The recrystallization temperature of the specimen subjected to three-step nitriding was elevated above 1873 K. The yield strength at 298 K obtained from nitrided Mo-0.5 wt% Ti alloy was about 1.6 times as high as that of the recrystallized specimen. Ductile-to-brittle transition temperature of nitrided Mo-0.5 wt% Ti alloy was about 181 K.
AB - In order to overcome the recrystallization embrittlement of molybdenum, internally nitrided dilute Mo-Ti alloy specimens having a heavily deformed surface microstructure were prepared by a novel three-step internal nitriding process at 1223-1873 K in N2 gas. Grain growth behavior and mechanical properties of nitrided specimens were investigated. Primary nitriding of the present alloys below their recrystallization temperature induced a uniform dispersion of ultrafine Ti-nitride precipitates without causing recrystallization. After secondary and tertiary nitriding, those precipitates grew into rod-like particles with a diameter of about 20 nm and a length of 50-120 nm, maintaining their deformed microstructure due to the pinning effect on grain boundary migration. The depth of the region where the recrystallization of the molybdenum matrix was suppressed was greatly dependent on the secondary nitriding temperature. The recrystallization temperature of the specimen subjected to three-step nitriding was elevated above 1873 K. The yield strength at 298 K obtained from nitrided Mo-0.5 wt% Ti alloy was about 1.6 times as high as that of the recrystallized specimen. Ductile-to-brittle transition temperature of nitrided Mo-0.5 wt% Ti alloy was about 181 K.
KW - Dilute Mo-Ti alloys
KW - Ductile-to-brittle transition temperature
KW - Multi-step internal nitriding
KW - Pinning effect
KW - Recrystallization temperature
KW - Ti-nitride precipitate
UR - http://www.scopus.com/inward/record.url?scp=26944458054&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=26944458054&partnerID=8YFLogxK
U2 - 10.1016/j.msea.2005.06.039
DO - 10.1016/j.msea.2005.06.039
M3 - Article
VL - 406
SP - 50
EP - 56
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
SN - 0921-5093
IS - 1-2
ER -