ISIJ International
Online ISSN : 1347-5460
Print ISSN : 0915-1559
ISSN-L : 0915-1559
Regular Article
Variant Selection of Reversed Austenite in Lath Martensite
Nobuo NakadaToshihiro TsuchiyamaSetsuo TakakiShuji Hashizume
Author information
JOURNALS FREE ACCESS

2007 Volume 47 Issue 10 Pages 1527-1532

Details
Abstract

The microstructure of partially reversed lath martensite in 13%Cr–6%Ni steel was examined by electron backscatter diffraction, and the crystallographic character of the reversed austenite is discussed in relation to the mechanism of ‘austenite memory’. Most of the reversed austenite grains had the same orientation as the original austenite matrix before martensitic transformation. However, some austenite grains had a different orientation in a twin relationship to the other major austenite grains, although all the reversed austenite grains retained a Kurdjumov–Sachs relationship to the martensite matrix. On the basis of the crystallographic relationships among the habit plane, the close packed direction of austenite and the martensite lath boundary, we suggest that the austenite variants are theoretically limited to two kinds within one packet and five kinds within one original austenite grain. In addition, we found that internal stress introduced by martensitic transformation plays an important role in determining the austenite variant: internal stress operates so that reversed austenite selects the same variant as that present in the original austenite matrix before martensitic transformation. This phenomenon is understood as the austenite memory.

Information related to the author
© 2007 by The Iron and Steel Institute of Japan
Previous article Next article
feedback
Top