TY - JOUR
T1 - Chemical diffusion in the iridium-rich A1 and L1 2 phases in the Ir-Nb system
AU - Numakura, Hiroshi
AU - Watanabe, Tatsuru
AU - Uchida, Makoto
AU - Yamabe-Mitarai, Yoko
AU - Bannai, Eisuke
N1 - Funding Information:
This work is partly supported by Grant-in-Aid for Scientific Research, Basic Research (C), 17560584, from the Ministry of Education, Culture, Sports, Science, and Technology, Japan.
PY - 2006/12
Y1 - 2006/12
N2 - The diffusion in iridium-rich Ir-Nh alloys has been studied by single-phase interdiffusion experiments. The chemical diffusion coefficient has been measured for the primary fee solid-solution and the L1 2 ordered compound Ir 3Nb in the temperature range between 1650 and 1950°C, using Ir/Ir-8Nb and Ir-26Nb/Ir-28Nb diffusion couples, respectively (numbers indicate mol%). While the chemical diffusion coefficient in the solid-solution phase is close to the tracer self-diffusion coefficient of pure iridium, the diffusion in the compound phase is extremely slow: the chemical diffusion coefficient is 1/40 to 1/50 of that in the solid solution. The low diffusion rate in the compound must be beneficial for high-temperature performance of refractory superalloys based on the Ir-Nb system.
AB - The diffusion in iridium-rich Ir-Nh alloys has been studied by single-phase interdiffusion experiments. The chemical diffusion coefficient has been measured for the primary fee solid-solution and the L1 2 ordered compound Ir 3Nb in the temperature range between 1650 and 1950°C, using Ir/Ir-8Nb and Ir-26Nb/Ir-28Nb diffusion couples, respectively (numbers indicate mol%). While the chemical diffusion coefficient in the solid-solution phase is close to the tracer self-diffusion coefficient of pure iridium, the diffusion in the compound phase is extremely slow: the chemical diffusion coefficient is 1/40 to 1/50 of that in the solid solution. The low diffusion rate in the compound must be beneficial for high-temperature performance of refractory superalloys based on the Ir-Nb system.
KW - Binary interdiffusion
KW - Chemical diffusion
KW - Intermetallic compound
KW - Iridium-niobium alloys
KW - Solid-solution
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U2 - 10.1361/154770306X153666
DO - 10.1361/154770306X153666
M3 - Article
AN - SCOPUS:33845792423
VL - 27
SP - 638
EP - 643
JO - Bulletin of Alloy Phase Diagrams
JF - Bulletin of Alloy Phase Diagrams
SN - 1547-7037
IS - 6
ER -