Cryo-quenched Fe–Ni–Cr alloy decorative steel single crystals II: Alloy phases, structure, hardness, tensile, tribological, magnetic and electronic properties

Journal Article · Sat Apr 11 00:00:00 EDT 2020 · Journal of Alloys and Compounds

DOI:https://doi.org/10.1016/j.jallcom.2020.155169· OSTI ID:1631255

Boatner, Lynn A.  ^[1]; Chakoumakos, Bryan C.  ^[1]; Pardhasaradhi, Sudharshan Phani ^[2]; Dryepondt, Sebastien N.  ^[1]; Shaw, Austin H. ^[1]; Qu, Jun  ^[1]; Marquez Rossy, Andres ^[1]; McGuire, Michael A.  ^[1]; Kolopus, James  ^[1]; Lara-Curzio, Edgar  ^[1]

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1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2. International Advanced Research Center for Powder Metallurgy and New Materials (ARCI) (India)

We have previously reported (Boatner et al., J. Alloys Compd. 691 (2017) 666–671) on the discovery, formation, processing, and application of a new decorative ternary steel alloy and on its use in a wide range of practical applications including: custom and commercial knives, art objects, jewelry, electronics, and furniture. This decorative property results when polished single crystals of the 70 wt%Fe-15 wt%Ni-15 wt% Cr austenitic alloy are cryo-quenched into the martensitic phase resulting in the formation of a three-dimensional raised pattern of mixed austenitic/martensitic laths. These laths propagate across large dimensions of the material due to the absence of grain boundaries in the single crystal. The macroscopic optically reflective 3-D decorative pattern reproduces the structural symmetry inherent in the single-crystal orientation. This pattern results solely from the metallurgical phase properties of the ternary alloy and is completely distinct from the properties of Damascus steels or more modern so-called pattern-welded steels. Here we use X-ray diffraction, nanoindentation, hardness measurements/scratch testing, tribological measurements, and alloy resistivity and magnetization methods to obtain a more fundamental and comprehensive study of the effects of the austenitic/martensitic phase transition on the structural and physical properties of the 70 wt%Fe-15 wt%Ni-15 wt% Cr alloy. These results reveal new insight into irreversible phenomena that are associated with the inhibited phase transition on heating of the two-phase, mixed austenitic/martensitic structure that is formed subsequent to cryo-quenching the alloy crystal to 77 K.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1631255
• Alternate ID(s): OSTI ID: 1616769
• Journal Information: Journal of Alloys and Compounds, Vol. 835, Issue C; ISSN 0925-8388
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Decorative steel
Phase transitions
Hardness
Tribology
Magnetism