Low-cycle fatigue behavior and surface treatment of a twinning-induced plasticity high-entropy alloy
Introduction
High- and medium-entropy approaches to alloy design have opened new pathways to obtain desired properties more conveniently when using various amounts of alloying elements [1,2]. The lower Gibbs free energy associated with higher configurational entropy prevents the formation of complex intermetallics and results in stable phases [3,4]. Despite the lower entropy of non-equiatomic variants of well-known CoCrFeMnNi high-entropy alloys (HEAs) compared to equiatomic variant (i.e., Cantor alloy), the former ones exhibit a strong resemblance to the latter [5,6]. Therefore, different deformation mechanisms such as transformation-induced plasticity and twinning-induced plasticity (TWIP) can be triggered using non-equiatomic HEAs. Despite the superior cryogenic fracture resistance of Cantor alloy, which is attributed to the activation of mechanical twinning [7], the high price of its alloying elements is a drawback for their use as industrial material. Fe40Mn40Co10Cr10 is a metastable HEA designed to be cheaper than Cantor alloy, but with more activation of mechanical twinning at room temperature [6,8].
Surface mechanical attrition treatment [9,10], severe shot peening [11], surface mechanical rolling treatment [12], and ultrasonic nanocrystal surface modification (UNSM) have been developed to introduce severe plastic deformation on the surfaces of materials. These surface treatment methods can significantly increase the volume fraction of mechanical twins (MTs), refine the grain size, and induce martensitic phase transformations near the surface of face-centered cubic (FCC) metals [10]. The residual stress and fine-grained structures generated on surfaces by these methods can improve strength and fatigue limits [[13], [14], [15]]. The UNSM, where a static load is imposed simultaneously with low-amplitude ultrasonic frequency vibrations, has been successful at producing ultrafine grains on the surfaces of HEAs [16,17].
To use HEAs in industrial applications, their cyclic deformation behavior and fatigue life must be investigated. Because MTs have been identified as strong barriers to fatigue crack growth [18,19], it is necessary to study the fatigue behavior of the Fe40Mn40Co10Cr10 HEA, which is also known as the TWIP HEA. Although there have been a few studies on the cyclic deformation behavior of Cantor alloy [[20], [21], [22], [23], [24]], there have been no reports on the fatigue performance of other cheaper variants. Additionally, the effects of UNSM on the low-cycle fatigue (LCF) behavior of different materials have not yet been investigated. Therefore, the strain-controlled fatigue life and effects of UNSM on the cyclic deformation behavior of the target HEA were studied and the underlying mechanisms were evaluated.
Section snippets
Experimental procedures
An ingot of Fe–40Mn–10Cr–10Co (at.%) with a weight of approximately 10 kg was produced using vacuum induction melting. A slab with dimensions of 100 × 70 × 30 mm was hot-rolled at 1100 °C through nine passes with a 10% thickness reduction in each pass to a final thickness of 12 mm. After homogenization heat treatment at 1200 °C for 2 h, cold rolling was performed through 10 passes with a 10% thickness reduction in each pass. Next, heat treatment was performed at 1100 °C for 30 min. Flat
Initial microstructure and tensile properties
The initial microstructure of the UT exhibited a uniform distribution of grain size with an average value of approximately 46.7 ± 19.6 μm (Fig. 2a) and a gradient microstructure was observed in the ST (Fig. 2b). UNSM resulted in a deformed microstructure near the surface in the ST. The cross-sectional EBSD image quality (IQ) map near the surface of the ST is presented in Fig. 2c, where various colors are used to represent boundaries with different misorientation angles. This map reveals that
Cyclic deformation behavior
The variation in the maximum stress with the number of cycles at different values is presented in Fig. 10. The cyclic hardening observed during the initial cycles in the UT is a typical behavior in FCC alloys and is attributed to the multiplication of primary dislocations [39]. Despite the slight softening observed in the UT following initial hardening at 0.85%, stability governed the cyclic behavior at 0.85% (Fig. 10a). The similar cyclic softening observed in the final stage
Conclusions
The cyclic deformation behavior of the metastable HEA Fe40Mn40Co10Cr10 (at.%), was studied through strain-controlled LCF tests. Additionally, the effects of UNSM on its tensile properties and fatigue life were investigated. The important conclusions drawn from this study are as follows.
- 1
Although a smaller amount of alloying elements led to a lower YS for the target HEA compared to the CoCrFeMnNi alloy, more activation of mechanical twinning as a result of its lower stacking fault energy resulted
CRediT authorship contribution statement
Seyed Amir Arsalan Shams: Writing – original draft, Methodology, Investigation, Formal analysis. Gyeonghyeon Jang: Investigation. Jae Wung Bae: Methodology, Writing – review & editing. Auezhan Amanov: Methodology, Writing – review & editing. Hyoung Seop Kim: Writing – review & editing, Supervision, Funding acquisition. Taekyung Lee: Writing – review & editing. Chong Soo Lee: Resources, Writing – review & editing, Supervision, Funding acquisition, Project administration.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
The authors appreciate Dr. Jae Nam Kim of GIFT, POSTECH for his contribution in TEM analysis.
References (54)
- et al.
A novel, single phase, non-equiatomic FeMnNiCoCr high-entropy alloy with exceptional phase stability and tensile ductility
Scripta Mater.
(2014) - et al.
Microstructural development in equiatomic multicomponent alloys
Mater. Sci. Eng. A
(2004) - et al.
Non-equiatomic high entropy alloys: approach towards rapid alloy screening and property-oriented design
Mater. Sci. Eng. A
(2015) - et al.
Design of a twinning-induced plasticity high entropy alloy
Acta Mater.
(2015) - et al.
An investigation of surface nanocrystallization mechanism in Fe induced by surface mechanical attrition treatment
Acta Mater.
(2002) - et al.
Formation of nanostructured surface layer on AISI 304 stainless steel by means of surface mechanical attrition treatment
Acta Mater.
(2003) - et al.
Surface severe plastic deformation of AISI 304 via conventional shot peening, severe shot peening and repeening
Appl. Surf. Sci.
(2015) - et al.
Gradient structure design to strengthen carbon interstitial Fe40Mn40Co10Cr10 high entropy alloys
Mater. Sci. Eng. A
(2020) - et al.
Gradient nanostructure and residual stresses induced by Ultrasonic Nano-crystal Surface Modification in 304 austenitic stainless steel for high strength and high ductility
Mater. Sci. Eng. A
(2014) - et al.
Fatigue properties of a S45C steel subjected to ultrasonic nanocrystal surface modification
Appl. Surf. Sci.
(2010)
A new guide for improving mechanical properties of non-equiatomic FeCoCrMnNi medium- and high-entropy alloys with ultrasonic nanocrystal surface modification process,
J. Mater. Sci. Technol.
Microstructure and mechanical properties of CoCrFeMnNi high entropy alloy with ultrasonic nanocrystal surface modification process
J. Mater. Sci. Technol.
Effect of the amount and temperature of prestrain on tensile and low-cycle fatigue properties of Fe-17Mn-0.5C TRIP/TWIP steel
Mater. Sci. Eng. A
Enhancing low-cycle fatigue life of commercially-pure Ti by deformation at cryogenic temperature
Mater. Sci. Eng. A
High-cycle fatigue and tensile deformation behaviors of coarse-grained equiatomic CoCrFeMnNi high entropy alloy and unexpected hardening behavior during cyclic loading
Intermetallics
Low-cycle fatigue properties of CoCrFeMnNi high-entropy alloy compared with its conventional counterparts
Mater. Sci. Eng. A
High-temperature low cycle fatigue behavior of an equiatomic CoCrFeMnNi high-entropy alloy
Mater. Sci. Eng. A
Effect of grain size on the low-cycle fatigue behavior of carbon-containing high-entropy alloys
Mater. Sci. Eng. A
On the comparison of graded microstructures developed through high reduction (per pass) cold rolling (HRCR) and ultrasonic nanocrystal surface modification (UNSM) in nickel-base alloy 602CA
Mater. Charact.
Unusual strain-induced martensite and absence of conventional grain refinement in twinning induced plasticity high-entropy alloy processed by high-pressure torsion
Mater. Sci. Eng. A
Joint contribution of transformation and twinning to the high strength-ductility combination of a FeMnCoCr high entropy alloy at cryogenic temperatures
Mater. Sci. Eng. A
Comparative study of the effects of surface mechanical attrition treatment and conventional shot peening on low cycle fatigue of a 316L stainless steel
Surf. Coating Technol.
Dislocation and twin substructure evolution during strain hardening of an Fe-22 wt.% Mn-0.6 wt.% C TWIP steel observed by electron channeling contrast imaging
Acta Mater.
Microstructure evolution and critical stress for twinning in the CrMnFeCoNi high-entropy alloy
Acta Mater.
Temperature-dependent universal dislocation structures and transition of plasticity enhancing mechanisms of the Fe40Mn40Co10Cr10 high entropy alloy
Int. J. Plast.
The effect of grain size and grain orientation on deformation twinning in a Fe-22wt.% Mn-0.6wt.% C TWIP steel
Mater. Sci. Eng.
Anomalous work hardening behavior of Fe40Mn40Cr10Co10 high entropy alloy single crystals deformed by twinning and slip
Acta Mater.
Cited by (11)
Ultrasonic nanocrystal surface modification effect on reduction of hydrogen embrittlement in Inconel-625 parts fabricated via additive manufacturing process
2023, Journal of Manufacturing ProcessesMicrostructure relevant fatigue short crack propagation behavior of Al<inf>0.3</inf>CoCrFeNi high entropy alloy: in-situ SEM study
2023, International Journal of FatigueRecent advances and outstanding challenges for implementation of high entropy alloys as structural materials
2023, Materials Today CommunicationsThe astonishing effect of Si addition on low-cycle fatigue life in a metastable high-entropy alloy
2023, Materials Science and Engineering: A