Defining a relationship between pearlite morphology and ferrite crystallographic orientation

• Published in: Acta materialia Vol. 129; pp. 278 - 289
• Main Authors: Durgaprasad, A., Giri, S., Lenka, S., Kundu, S., Mishra, S., Chandra, S., Doherty, R.D., Samajdar, I.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2017
• Subjects: EBSD; Pearlite; Residual stress; Texture; Volume change; Volume change; Texture; Pearlite; EBSD; Residual stress
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2017.02.008

This study involved fully pearlitic wires of seven different diameters (5.5–1.6 mm). All samples were laboratory annealed to re-austenitize and were then air-cooled to reform the pearlite structure. Morphological alignment of the pearlite, along the wire axis, improved significantly, 32% to 93%, as the wire diameter decreased. This improvement coincided with increases in the ferrite fiber texture, and falls in the axial residual stresses. In all the wires, the majority of the pearlite lamellae appeared to align, in a 2-D analysis, with minimum elastic stiffness (EMin under simple compression) for the ferrite (α). This correlation increased from 80% to 98% with decrease in wire diameter and fall in axial residual stresses. 3-D microstructures by serial sectioning, 3-D rotations seeking EMin and observations on coarse pearlite, indicated that {011}α and α were, respectively, the pearlite interface (or habit plane) and growth direction. [Display omitted]