###### Abstract  
The development of FeCrAl alloys has commenced for use as nuclear fuel cladding material, intended to serve as an enhanced accident-tolerant alternative to Zr-based alloys. In this study, the Fe-13 Cr-4 Al alloy, specifically designed for advanced accident-tolerant fuel (ATF) cladding, was carefully prepared through vacuum induction melting and hot-working processes. Mechanical properties and serrated flow behavior of this alloy were investigated through tensile tests at temperatures ranging from 200 to 800 \({}^{\circ}\)C. Intriguingly, serrations emerged within a specific temperature range, accompanied by unique mechanical behavior characteristics indicative of dynamic strain aging (DSA). Additionally, the alloy's fracture modes showed a transition from a mix of ductile and cleavage fracture features to fully ductile fracture as the temperature increased. This study offers insights into the mechanical properties and serration behaviors of FeCrAl alloys, highlighting their potential for use in nuclear fuel cladding. FeCrAl alloy; serration; mechanical properties; dynamic strain aging; fracture mode +
Footnote †: journal: Applied Sciences  
1
Footnote 1: School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, China 1  
Footnote 2: China Nuclear Power Engineering Co., Ltd., Beijing 100840, China 2  
(PLC) effect. The PLC effect stems from dynamic strain aging (DSA), which relies on the interplay between mobile dislocations and solute atoms [16; 17]. Specifically, it involves the repetitive pinning and depinning actions of solute atoms on mobile dislocations during the process of plastic deformation. Several types of alloys, such as steels [18; 19; 20], aluminum-based alloys [21; 22], nickel-based alloys [23; 24], and high-entropy alloys [25; 26], have demonstrated the occurrence of serrated flow during plastic deformation. It is worth noting that only a limited number of studies have reported the occurrence of serrated flow behavior in FeCrAl alloys within a specific range of deformation temperatures [27; 28; 29; 30]. For instance, [PERSON] et al. [27] examined the tensile behaviors of neutron-irradiated Fe-21.5 Cr-5 Al alloy at 320 \({}^{\circ}\)C and observed a pronounced serration behavior of the irradiated specimens. However, the study did not examine the relationship between serration characteristics and different deformation conditions. [PERSON] and [PERSON] [28] studied the tensile behaviors of the Fe-21.5 Cr-5.0 Al-3.1 Mo alloy in a broad temperature range from ambient temperature to 500 \({}^{\circ}\)C. Their analysis revealed the presence of serration behavior with different types in the stress-strain curves within the temperature range of 250-400 \({}^{\circ}\)C. In a subsequent investigation by the same research group [29], serrations were observed during the tensile deformation of two FeCrAl alloys (Fe-21.5 Cr-5.0 Al-3.1 Mo and Fe-22 Cr-5 Al-0.1Y-0.1 Zr) at intermediate temperatures of 225-350 \({}^{\circ}\)C caused by DSA. [PERSON] et al. [30] observed the serrations in the stress-strain curves of the Fe-20 Cr-5 Al alloy in the temperature range of 200-400 \({}^{\circ}\)C at a constant strain rate of 3.333 \(\times\) 10\({}^{-4}\) s\({}^{-1}\). Moreover, peaks in the tensile strength and strain-hardening exponent, and a plateau in the yield strength, occurred in this temperature range. Despite the aforementioned studies reporting on the serrated flow behaviors of FeCrAl alloys, research in this area has predominantly concentrated on alloys with high chromium contents, exceeding 20 wt.%. There remains a significant gap in our understanding of how deformation temperature impacts the high-temperature mechanical properties and serrated flow behaviors of FeCrAl alloys with lower chromium contents. Additionally, it has been reported that the PLC effect detrimentally influences the material's surface quality, processability, and mechanical properties, such as tensile ductility and low-cycle fatigue life [19; 24; 31].