Deformation-induced dissolution of the intermetallics Ni₃Ti and Ni₃Al in austenitic steels at cryogenic temperatures

Abstract

An anomalous deformation-induced dissolution of the intermetallics Ni₃Al and Ni₃Ti in the matrix of austenitic Fe–Ni–Al(Ti) alloys has been revealed in experiment at cryogenic temperatures (down to 77 K) under rolling and high pressure torsion. The observed phenomenon is explained as the result of migration of deformation-stipulated interstitial atoms from a particle into the matrix in the stress field of moving dislocations. With increasing the temperature of deformation, the dissolution is replaced by the deformation-induced precipitation of the intermetallics, which is accelerated due to a sufficient amount of point defects in the matrix, gained as well in the course of deformation at lower temperatures.

Keywords:

• Fe–Ni austenite
• intermetallics
• deformation-induced dissolution
• cryogenic temperatures
• mössbauer spectroscopy

Acknowledgments

Authors are grateful to Ustyugov Yu. M., Afanasiev S. V., Zamatovskii A. E. and Lyashkov K. A. for their help in the work performed.