Neutron diffraction in situ monitoring of the dislocation density during martensitic transformation in a stainless steel

In situ monitoring of the dislocation density during martensitic transformation, and annealing, of the martensitic stainless steel 17-4PH was undertaken using neutron diffraction. The dislocation density in martensite is seen to increase linearly from similar to 2 x 10(15) to similar to 4 x 10(15) m(-2) during the transformation. In addition, the dislocation density in the parent phase (austenite) slowly increases from similar to 0 to 10(15) m(-2). Annealing of the newly formed martensite in the temperature range 500-700 degrees C leads to almost complete elimination of dislocations. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.