Key Takeaways & Executive Findings
- •• Hot compression of high-purity silver was systematically investigated using a Gleeble-3800 thermal simulator across strain rates of 0.001–10 s⁻¹ and temperatures of 250–400 °C. • An Arrhenius constitutive equation and processing maps were developed to predict deformation behavior and optimize hot working parameters. • Plastic instability occurs at high strain rates, while the optimal processing window is a strain rate below 0.001 s⁻¹ and a temperature range of 340–400 °C. • Dynamic recovery dominates at lower temperatures (e.g., 250 °C) due to low stacking fault energy, while dynamic recrystallization becomes pronounced with increasing temperature and saturates at 350 °C.
Abstract
High-purity silver (Ag) is extensively utilized in electronics, aerospace, and other advanced industries due to its excellent thermal conductivity, electrical conductivity, and machinability. However, the prohibitive material cost poses substantial challenges for optimizing thermal processing parameters through repetitive experimental trials. In this work, hot compression experiments on high-purity silver were conducted using a Gleeble-3800 thermal simulator. The high-temperature deformation behaviors, dynamic recovery (DRV) and dynamic recrystallization (DRX) of high-purity silver were studied by constructing an Arrhenius constitutive equation and developing thermal processing maps. The results show that plastic instability of high-purity silver occurs at high strain rates and the optimized hot processing parameters are the strain rate below 0.001 s−1 and the temperature of 340−400 ℃. Microstructural observations exhibit that DRV prefers to occur at lower deformation temperatures (e.g., 250 ℃). This is attributed to the low stacking fault energy of high-purity silver, which facilitates the decomposition of dislocations into partial dislocations and promotes high-density dislocation accumulation. Furthermore, DRX in high-purity silver becomes increasingly pronounced with increasing deformation temperature and reaches saturation at 350 ℃.
1. Introduction
Due to its excellent elongation, high conductivity and ornamental value, high-purity silver (Ag) (≥99.99 wt.%) has been widely used in electronic, aerospace, and jewelry fields [1−5]. High-purity Ag products are usually prepared by rolling, forging, and coining methods, among which, hot rolling is an indispensable processing technique for the batch preparation of Ag foil materials [6−8]. By optimizing the hot rolling parameters, the dynamic recovery and recrystallization processes can be enhanced, thereby tailoring the microstructure of Ag and improving the tensile strength and fracture toughness. For example, GHOLAMI et al [9] prepared Al/Ag double-layer sheets via rolling process and studied the effects of different annealing treatments on the microstructure and ductile fracture behavior of the composites.
On the other hand, to improve the hot-processing parameters of high-purity Ag materials, it is necessary to investigate the evolution of flow stress in the material at various temperatures. The flow stress represents the minimum stress for dislocations to continuously pass through metal crystals during deformation, and it is strongly related to the deformation temperature, strain rate, and maximum strain degree [7, 10−12]. By analyzing the constitutive relationship during the deformation processes, the flow stress model can be established, which relates the deformation temperature, deformation rate, and strain to the microstructure of the material. In addition, the establishment of proper processing maps based on the flow stress model can predict the stable deformation regions of metal materials, and avoid internal microscopic defects caused by instable plastic deformations. Therefore, the establishment of processing maps plays the significant role in the optimization of hot rolling parameters for high-purity Ag.
However, the optimization of the hot rolling process for Ag is significantly constrained by the high cost of raw materials and the prolonged processing cycle, rendering repeated experimental trials impractical. A review of the current literatures [13−17] reveal that most studies concentrate on the effects of processing deformation and heat treatment on the microstructure and properties of Ag and Ag-based composites. In contrast, there is limited research that elaborates on the microstructure evolution of pure Ag during hot processing. Moreover, few studies analyze the effects of deformation temperature, deformation rate, and strain on the flow stress based on the constitutive model. In the present work, the hot compression tests were conducted on the high-purity Ag with the strain rates of 0.001−10 s−1 at 250−400 ℃. Based on the compressive true stress −true strain curves of high-purity Ag, the constitutive model and processing maps were established. The microstructure of the samples was characterized after compression under various conditions to reveal the underlying mechanisms of microstructure evolution.
Loading authentic research manuscript (Pages 1–5)...
YAO Ying-jun, WEN Jing, YAN Shuai-jiang, WANG Ri-chu, PENG Xiang, CAI Zhi-yong (2025). Hot compression deformation behavior and microstructural characteristics of high-purity silver. Journal of Central South University. https://doi.org/10.1007/s11771-025-5946-y
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
Copyright & Intellectual Property Notice: Original copyright of the underlying source articles and experimental data remains with the respective authors, institutions, and original publishing journals. SinoTechIntel claims intellectual property only over its proprietary translations, analytical syntheses, and AEO structured enhancements in accordance with international fair use and academic citation principles.
Frequently Asked Questions
What are the optimized hot processing parameters for high-purity silver?
According to the study, the optimized parameters are a strain rate below 0.001 s⁻¹ and a temperature range of 340–400 °C to avoid plastic instability.
What are the main microstructural mechanisms during hot deformation of high-purity silver?
The material exhibits dynamic recovery (DRV) at lower temperatures (e.g., 250 °C) and dynamic recrystallization (DRX) at higher temperatures. DRX becomes more pronounced with increasing temperature and saturates at 350 °C.
How was the constitutive model developed?
An Arrhenius constitutive equation was constructed based on the true stress–true strain curves obtained from hot compression tests using a Gleeble-3800 thermal simulator.
Why is it important to study the processing map of high-purity silver?
Processing maps help predict stable deformation regions and avoid internal defects caused by plastic instability, which is crucial for optimizing hot rolling parameters given the high cost of silver.
Why does dynamic recovery prefer lower temperatures in high-purity silver?
Because high-purity silver has low stacking fault energy, which facilitates the decomposition of dislocations into partial dislocations, leading to high-density dislocation accumulation that promotes dynamic recovery at lower temperatures.
Related Technical Papers & Translations
Design and optimization of a high-efficiency distillation process for cellulosic fuel ethanol integrated with thermal coupling and molecular sieve adsorption
To address the challenges of high energy consumption and prominent costs in the traditional three-columns distillation process for cellulosic fuel ethanol, a distillation—molecular sieve coupling separation process is proposed. This process integrates a three-column (crude distillation column, first distillation column, second distillation column) system with a 3A molecular sieve adsorption deep dehydration unit. A thermal coupling network is constructed via differential pressure design (steam from medium/high-pressure columns as mutual heat sources, reboiler liquid waste heat for feed preheating), and molecular sieve adsorption conditions are optimized. The study first performs a thermodynamic consistency test on the ethanol—water system, determines optimal non-random two-liquid (NRTL) model binary interaction parameters via experimental data regression for Aspen Plus simulation. Aiming at minimum total annual cost (TAC), Aspen Plus is used to optimize process parameters (theoretical tray number, feed location, reflux ratio, side-draw position, etc.). Economic analysis shows this process reduces CO2 emission costs by 27.56%, TAC by 15.58% (to 5.123 × 106 USD·a-1), and increases ethanol purity to ＞99.6%, providing an effective solution for green, efficient separation.
A cohesion loss model for determining residual strength of deep bedded sandstone
Rock residual strength, as an important input parameter, plays an indispensable role in proposing the reasonable and scientific scheme about stope design, underground tunnel excavation and stability evaluation of deep chambers. Therefore, previous residual strength models of rocks established were reviewed. And corresponding related problems were stated. Subsequently, starting from the effects of bedding and whole life-cycle evolution process, series of triaxial mechanical tests of deep bedded s
Federated model with contrastive learning and adaptive control variates for human activity recognition
Recent attention to privacy issues demands a communication-safe method for training human activity recognition (HAR) models on client activity data. Federated learning (FL) has become a compelling technique to facilitate model training between the server and clients while preserving data privacy. However, classical FL methods often assume independent and identically distributed (IID) data among clients. This assumption does not hold true in practical scenarios. Human activity in real-world scena