TY - JOUR
T1 - Effect of Transformation Cycling on the ε Martensitic Transformation in Fe-Mn Alloys
AU - Tsuzaki, Kaneaki
AU - Maki, Tadashi
N1 - Copyright:
Copyright 2016 Elsevier B.V., All rights reserved.
PY - 1990
Y1 - 1990
N2 - The effect of γ⇆ε cyclic transformation on the subsequent forward and reverse transformations was studied in low carbon Fe-17%Mn and Fe-25%Mn binary alloys. A remarkable decrease in Ms temperature by the cyclic transformation was observed in the Fe-25%Mn alloy. After 7 thermal cycles between 305 and 573 K, Ms decreased by over 60 K and the structure became fully austenitic at room temperature. On the other hand, As and Af temperatures increased with an increase in the number of thermal cycles. As the upper peak temperature of thermal cycling increased, the changes in Ms, As and Af became smaller. The decrease in Ms by the cyclic transformation was smaller in the Fe-17%Mn alloy than in the Fe-25%Mn alloy. A large number of dislocations were observed in the austenite of the Fe-25%Mn alloy after the thermal cycling between 273 and 573 K, although dislocations were scarcely observed before the thermal cycling. The hardness of austenite at 573 K was markedly increased by the thermal cycling between 273 and 573 K. A microstructure memory, which is a phenomenon that martensite forms in the same position where the martensite formed in the last forward transformation, was not observed.
AB - The effect of γ⇆ε cyclic transformation on the subsequent forward and reverse transformations was studied in low carbon Fe-17%Mn and Fe-25%Mn binary alloys. A remarkable decrease in Ms temperature by the cyclic transformation was observed in the Fe-25%Mn alloy. After 7 thermal cycles between 305 and 573 K, Ms decreased by over 60 K and the structure became fully austenitic at room temperature. On the other hand, As and Af temperatures increased with an increase in the number of thermal cycles. As the upper peak temperature of thermal cycling increased, the changes in Ms, As and Af became smaller. The decrease in Ms by the cyclic transformation was smaller in the Fe-17%Mn alloy than in the Fe-25%Mn alloy. A large number of dislocations were observed in the austenite of the Fe-25%Mn alloy after the thermal cycling between 273 and 573 K, although dislocations were scarcely observed before the thermal cycling. The hardness of austenite at 573 K was markedly increased by the thermal cycling between 273 and 573 K. A microstructure memory, which is a phenomenon that martensite forms in the same position where the martensite formed in the last forward transformation, was not observed.
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U2 - 10.2355/isijinternational.30.666
DO - 10.2355/isijinternational.30.666
M3 - Article
AN - SCOPUS:0025593591
VL - 30
SP - 666
EP - 673
JO - Transactions of the Iron and Steel Institute of Japan
JF - Transactions of the Iron and Steel Institute of Japan
SN - 0915-1559
IS - 8
ER -