Authors: Debasis Poddar Pavel Cizek Hossein Beladi Peter D Hodgson
Publish Date: 2015/10/01
Volume: 46, Issue: 12, Pages: 5933-5951
Abstract
The present work was aimed at a detailed investigation of the orientation dependence of the microstructure characteristics in a Fe30NiNb austenitic model steel subjected to hot uniaxial compression at 1198 K 925 °C at a strain rate of 1 s−1 to several strain levels up to 10 The quantification of the substructure evolution as a function of strain was performed for the stable 〈011〉 oriented grains Other grain orientations were also investigated in detail at a strain of 02 The 〈110〉 oriented grains contained selfscreening arrays of “microbands” MBs aligned with high Schmid factor 111 slip planes The MB crystallographic alignment was largely maintained up to a strain of 10 which suggests that the corresponding boundaries kept continuously rearranging themselves during straining and did not follow the sample shape change The mean MB spacing decreased and misorientation angle increased with strain towards saturation indicating the operation of the “repolygonization” dynamic recovery mechanism The non〈011〉 oriented grains displayed a strong tendency to split during deformation into deformation bands having alternating orientations and being mutually rotated by large angles The bands were separated by transition regions comprising arrays of closely spaced extended subboundaries collectively accommodating large misorientations across very small distances
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