Invariant plastic deformation mechanism in paramagnetic nickel-iron alloys

Zhihua Dong; Wei Li; Stephan Schönecker; Bin Jiang; Levente Vitos

doi:10.1073/pnas.2023181118

Invariant plastic deformation mechanism in paramagnetic nickel-iron alloys

Proc Natl Acad Sci U S A. 2021 Apr 6;118(14):e2023181118. doi: 10.1073/pnas.2023181118.

Authors

Zhihua Dong^{1

2

3}, Wei Li³, Stephan Schönecker³, Bin Jiang^{4

2}, Levente Vitos^{5

6

7}

Affiliations

¹ State Key Laboratory of Mechanical Transmissions, College of Materials Science and Engineering, Chongqing University, 400044 Chongqing, China; dzhihua@cqu.edu.cn levente@kth.se.
² National Engineering Research Center for Magnesium Alloys, Chongqing University, 400044 Chongqing, China.
³ Applied Materials Physics, Department of Materials Science and Engineering, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden.
⁴ State Key Laboratory of Mechanical Transmissions, College of Materials Science and Engineering, Chongqing University, 400044 Chongqing, China.
⁵ Applied Materials Physics, Department of Materials Science and Engineering, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden; dzhihua@cqu.edu.cn levente@kth.se.
⁶ Department of Physics and Astronomy, Division of Materials Theory, Uppsala University, SE-75120 Uppsala, Sweden.
⁷ Research Institute for Solid State Physics and Optics, Wigner Research Center for Physics, H-1525 Budapest, Hungary.

Abstract

The Invar anomaly is one of the most fascinating phenomena observed in magnetically ordered materials. Invariant thermal expansion and elastic properties have attracted substantial scientific attention and led to important technological solutions. By studying planar faults in the high-temperature magnetically disordered state of [Formula: see text], here we disclose a completely different anomaly. An invariant plastic deformation mechanism is characterized by an unchanged stacking fault energy with temperature within wide concentration and temperature ranges. This anomaly emerges from the competing stability between the face-centered cubic and hexagonal close-packed structures and occurs in other paramagnetic or nonmagnetic systems whenever the structural balance exists. The present findings create a platform for tailoring high-temperature properties of technologically relevant materials toward plastic stability at elevated temperatures.

Keywords: Invar; high-temperature alloys; paramagnetism; plasticity.