High-Temperature Deformation Behaviors of the C-Doped and N-Doped High Entropy Alloys

Abstract

High entropy alloys (HEAs) containing multi-principal metallic constituents have attracted much attention. A good understanding of their hot-deformation behavior and recrystallization mechanism is the prerequisite for microstructures tuning and for optimizing mechanical performance. Here, the flow behavior and recrystallization mechanism of the N-doped and C-doped face-centered cubic phase HEAs are produced at high temperatures by hot-compression at 1123–1273 K, with strain rates of 0.1–0.001 s−1. Constitutive equations were successfully constructed to reveal flow behavior, and stress-strain curves were predicted using strain compensated polynomial functions. Discontinuous and continuous dynamic recrystallization proceeded concurrently when compressed at a low temperature and high strain rate, whereas discontinuous recrystallization, which occurs at primary grain boundaries, became predominant at a high temperature and low strain rate, significantly contributing to the refinement and homogenization of the grains. For this reason, a relatively high temperature and a low strain rate, in which the recrystallized grains exhibit equiaxed morphology and very weak texture, are more suitable for refining grains. The average size of the grains was approximately 10 μm. This study sheds light on grain optimization and mechanical properties through thermomechanical processing.

Translating strain to stress: a single-layer Bi-LSTM approach to predicting stress-strain curves in alloys during hot deformation

“…The SCS model, expressed as equation (7), is recognized for its effectiveness in capturing deformation behaviors under various conditions, often outperforming other constitutive models across different alloys [18,19]. Therefore, it serves as an appropriate benchmark for the comparative analysis.…”

“…Sellars and colleagues [15][16][17] developed the hyperbolic-type Arrhenius equation, termed as the Sellars model, to evaluate the influence of strain rates and temperatures on flow stress under steady condition. Furthermore, a strain-compensated Sellars (SCS) model [18][19][20][21] was proposed, considering the effect of strain on the parameters of the original Sellars model.…”

Tuning Microstructure and Mechanical Performance of a Co-Rich Transformation-Induced Plasticity High Entropy Alloy

“…However, the mechanical properties have only been reported for as-recrystallized Co-rich HEAs. The microstructure has a strong correlation with the mechanical properties of metals and alloys, which are usually tuned by thermomechanical processing (TMP), such as rolling, compression, and torsion, combined with heat-treatment [20][21][22][23][24][25][26][27][28][29]. The influence of TMP on the resultant microstructure and the correlation between the microstructure and mechanical performance of the newly developed Co-rich HEAs have not yet been revealed.…”