Bainite formation influenced by large stress

Abstract

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.