TY - JOUR
T1 - Phase selection for undercooled Ti-46Al-7Nb hypo-peritectic alloy
AU - He, Tan
AU - Hu, Rui
AU - Wang, Jun
AU - Zhang, Tie Bang
AU - Kou, Hong Chao
AU - Li, Jin Shan
PY - 2014/6
Y1 - 2014/6
N2 - The rapid solidification of undercooled Ti-46Al-7Nb alloy was investigated by in situ observation of recalescence events during electromagnetic levitation. A maximum melt undercooling up to 240 K has been achieved. Levitated drops of controlled undercooling were quenched onto chill copper substrate and subjected to phase and microstructure analysis. Beyond a critical undercooling of 205 K, solidification mode changes from peritectic transformation into suppression of peritectic transformation. When the intial undercooling (δT) is lower than a critical value (δT*), the solidification follows a typical manner of peritectic alloys, i.e. β phase solidifies as primary phase, after which, peritectic α phase forms through peritectic growth which is controlled by peritectic reaction, peritectic transformation. If δT≤δT*, the formation of peritectic α phase will be suppressed, and the solidification of single β phase will prevail.This phenomenon can be explained by comparing the relationship between incubation time for peritectic reaction (τP) and post-recalescence time corresponding to pure β phase solidification (tβ). When the undercooling is no different, microstructure can obtain the β/α″ martensitic transformation by changing the cooling rate.
AB - The rapid solidification of undercooled Ti-46Al-7Nb alloy was investigated by in situ observation of recalescence events during electromagnetic levitation. A maximum melt undercooling up to 240 K has been achieved. Levitated drops of controlled undercooling were quenched onto chill copper substrate and subjected to phase and microstructure analysis. Beyond a critical undercooling of 205 K, solidification mode changes from peritectic transformation into suppression of peritectic transformation. When the intial undercooling (δT) is lower than a critical value (δT*), the solidification follows a typical manner of peritectic alloys, i.e. β phase solidifies as primary phase, after which, peritectic α phase forms through peritectic growth which is controlled by peritectic reaction, peritectic transformation. If δT≤δT*, the formation of peritectic α phase will be suppressed, and the solidification of single β phase will prevail.This phenomenon can be explained by comparing the relationship between incubation time for peritectic reaction (τP) and post-recalescence time corresponding to pure β phase solidification (tβ). When the undercooling is no different, microstructure can obtain the β/α″ martensitic transformation by changing the cooling rate.
KW - Critical undercooling
KW - Hypo-peritectic alloy
KW - Microstructure
UR - http://www.scopus.com/inward/record.url?scp=84904397063&partnerID=8YFLogxK
M3 - 文章
AN - SCOPUS:84904397063
SN - 1673-0224
VL - 19
SP - 355
EP - 360
JO - Fenmo Yejin Cailiao Kexue yu Gongcheng/Materials Science and Engineering of Powder Metallurgy
JF - Fenmo Yejin Cailiao Kexue yu Gongcheng/Materials Science and Engineering of Powder Metallurgy
IS - 3
ER -