TY - GEN
T1 - Alloy design of Nb-Si based high temperature alloys by phase stability control
AU - Miura, Seiji
AU - Tanahashi, Tatsuichi
AU - Mishima, Yoshinao
AU - Mohri, Tetsuo
N1 - Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2010
Y1 - 2010
N2 - In order to spheroidize α-Nb5Si3 strengthening phase embedded in Nb matrix for attaining a good room temperature toughness of Nb-Si alloy, the authors have proposed a microstructure control technique by combining eutectic and eutectoid reactions. Nb3Si intermetallic compound formed during solidification is a key phase for the microstructure control, but its stability is very sensitive to the alloying elements. Nb 3Si disappears by adding as small as 3 at% of W and Mo, while these elements are very effective for the solid solution strengthening of Nb phase. For a further alloy development, establishment of an alloy design concept based on the control of phase stability of Nb3Si is needed. Similarly to ferrous alloys such as stainless steels where Cr and Ni are added to control the stability of bcc phase and fcc phase, two alloying elements (one is a stabilizing element and the other is a destabilizing element for Nb 3Si phase) are added to a Nb-Si binary master alloy and their microstructure is investigated using SEM. The stabilizing element Ta is found to enlarge the composition area where Nb3Si exists even with the destabilizing element Mo, and it is confirmed that the phase stability concept is useful for designing Nb-Si based alloys.
AB - In order to spheroidize α-Nb5Si3 strengthening phase embedded in Nb matrix for attaining a good room temperature toughness of Nb-Si alloy, the authors have proposed a microstructure control technique by combining eutectic and eutectoid reactions. Nb3Si intermetallic compound formed during solidification is a key phase for the microstructure control, but its stability is very sensitive to the alloying elements. Nb 3Si disappears by adding as small as 3 at% of W and Mo, while these elements are very effective for the solid solution strengthening of Nb phase. For a further alloy development, establishment of an alloy design concept based on the control of phase stability of Nb3Si is needed. Similarly to ferrous alloys such as stainless steels where Cr and Ni are added to control the stability of bcc phase and fcc phase, two alloying elements (one is a stabilizing element and the other is a destabilizing element for Nb 3Si phase) are added to a Nb-Si binary master alloy and their microstructure is investigated using SEM. The stabilizing element Ta is found to enlarge the composition area where Nb3Si exists even with the destabilizing element Mo, and it is confirmed that the phase stability concept is useful for designing Nb-Si based alloys.
KW - Microstructure control
KW - NbSi
KW - Schaeffler's diagram
KW - Spheroidization
KW - α-NbSi
UR - http://www.scopus.com/inward/record.url?scp=77955477439&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77955477439&partnerID=8YFLogxK
U2 - 10.4028/www.scientific.net/MSF.654-656.444
DO - 10.4028/www.scientific.net/MSF.654-656.444
M3 - Conference contribution
AN - SCOPUS:77955477439
SN - 0878492550
SN - 9780878492558
T3 - Materials Science Forum
SP - 444
EP - 447
BT - PRICM7
PB - Trans Tech Publications Ltd
T2 - 7th Pacific Rim International Conference on Advanced Materials and Processing, PRICM-7
Y2 - 2 August 2010 through 6 August 2010
ER -