In recent years, high-entropy alloys (HEAs) have attracted considerable attention in materials engineering due to their unique phase stability and mechanical properties compared to conventional alloys. Since the inception of HEAs, CoCrFeMnNi alloys have been widely investigated due to their outstanding strength and fracture toughness at cryogenic temperatures. However, their lower yield strength at room temperature limits their structural applications. The mechanical properties of HEAs are greatly influenced by their processing methods and microstructural features. Unlike traditional melting techniques, powder metallurgy (PM) provides a unique opportunity to produce HEAs with nanocrystalline structures and uniform compositions. The current review explores recent advances in optimizing the microstructural characteristics in CoCrFeMnNi HEAs by using PM techniques to improve mechanical performance. The most promising strategies include grain refinement, dispersion strengthening, and the development of heterogeneous microstructures (e.g., harmonic, bimodal, and multi-metal lamellar structures). Thermomechanical treatments along with additive manufacturing techniques are also summarized. Additionally, the review addresses current challenges and suggests future research directions for designing advanced HEAs through PM techniques.
Climatic change affects agricultural, environmental and livestock production. Forage productivity is highly dependent on the weather change. The Pyeongchang region has more difficulty in cultivation of Sorghum-Sudangrass hybrids (SSH) than other warm regions because of the cold weather. This experiment was carried out to analysis the agronomic characteristics, productivity, and nutritive value of three cultivars of Sorghum-Sudangrass hybrids in the Pyeongchang region from 2021 to 2022. Two harvests were taken in each year, and the agronomic characteristics, dry matter yield, and nutrient content of the whole SSH crops were determined. The plant height ranged between 281-291 cm and 165-172 cm in the first and second harvest, respectively. Plant height of Superdan (291±49 cm) was the highest in the first cut and Dairy mens Dream (172±30 cm) was the highest in the second cut time. Stem diameter ranged from 9.5 to 8.8 mm with Superdan having a higher level than the other two cultivars. The Dairy mens Dream variety produced significantly higher dry matter yield (15,695 kg/ha) than those of Superdan (14,584 kg/ha) and Supergreen (14,300 kg/ha) over a two-year experimental period. In terms of nutritional quality, the crude protein content, neutral detergent fiber and acid detergent fiber of SSH cultivars were analysed. There were no significant changes in the content of CP, ADF and NDF ranges among the cultivars. In addition, the Superdan cultivar had slightly higher CP content (10.17%) and was followed by Dairy mens Dream (9.84%) and Supergreen (9.54%) in the second cut time of 2-year average. Dairy mens dream had lower ADF and NDF values than other cultivars; however, no significant differences amongst cultivars in fiber content were observed. Therefore, these three cultivars displayed the potential growth characteristics, DM yield and nutritive values in Pyeongchang region. Hence, the SSH cultivars have a potential to withstand the climatic change and improve SSH productivity in the study area.