Twinning and martensitic transformations in nickel-enriched 304 austenitic steel during tensile and indentation deformations

Journal Article · Tue Jan 01 00:00:00 EST 2013 · Materials Science and Engineering A

DOI:https://doi.org/10.1016/j.msea.2013.08.072· OSTI ID:1110930

Gussev, Maxim N ^[1]; Busby, Jeremy T ^[1]; Byun, Thak Sang ^[1]; Parish, Chad M ^[1]

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1. ORNL

Twinning and martensitic transformation have been investigated in nickel-enriched AISI 304 stainless steel subjected to tensile and indentation deformation. Using electron backscatter diffraction (EBSD), the morphology of alpha- and epsilon-martensite and the effect of grain orientation to load axis on phase and structure transformations were analyzed in detail. It was found that the twinning occurred less frequently under indentation than under tension; also, twinning was not observed in [001] and [101] grains. In tensile tests, the martensite particles preferably formed at the deformation twins, intersections between twins, or at twin-grain boundary intersections. Conversely, martensite formation in the indentation tests was not closely associated with twinning; instead, the majority of martensite was concentrated in the dense colonies near grain boundaries. Martensitic transformation seemed to be obstructed in the [001] grains in both tensile and indentation test cases. Under a tensile stress of 800 MPa, both alpha- and epsilon-martensite were found in the microstructure, but at 1100 MPa only -martensite presented in the specimen. Under indentation, alpha- and epsilon-martensite were observed in the material regardless of stress level.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Shared Research Equipment Collaborative Research Center
• Sponsoring Organization: USDOE
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1110930
• Journal Information: Materials Science and Engineering A, Vol. 588; ISSN 0921-5093
• Country of Publication: United States
• Language: English