An Experimental Study of the Crystallography of the Austenite Bainite Reaction
Description:... Crystallographic data were obtained for the austenite-bainite reaction in a steel containing 6% Mn and 1% C at temperatures ranging from 260 to 538 C. To obtain accurate crystallographic data on the finely divided structures typical of bainite it was necessary to devise improved experimental methods for determination of the habit plane and orientation relationship between the two phases. These methods are generally applicable to situations in which the product phase consists of very small plates. Habit plane data were obtained by cutting a crystal of the parent phase to a low-index, predetermined orientation, such as (100), or (111); it was then possible to calculate the habit plane indices from the angles observed between the habit plane traces using trigonometric relationships. The orientation relationship was obtained by using a single crystal orienter mounted on a diffractometer, permitting the sample orientation to be varied continuously during irradiation. The use of (100) planes of both phases allowed the transformation matrix to be calculated analytically from the observations.
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