By using an iron alloy that transforms slowly to bainite at a low temperature, it has been possible to study the
development of the upper bainite under the influence of exceptionally large stresses, which are nevertheless below
the yield strength of the parent austenite. It is found that a uniaxial stress whose magnitude is below the elastic
limit, strongly favours the growth of compliant variants, leading to an organised microstructure. It also accelerates
the overall rate of reaction. A comparison between samples transformed with and without an applied stress revealed
significant changes in the crystallographic texture, consistent with the observed microstructures. Stress assisted
transformation resulted in large blocks of bainite in identical orientation.
JFE Steel Corp., Japan and the
EPSRC UK
Peer reviewed