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The fabrication of high-entropy alloys (HEAs) using metal injection molding (MIM) represents a significant leap forward in the field of materials engineering, enabling the production of components with complex shapes while maintaining the unique mechanical properties of HEAs. This study investigates the effect of heating rate variations on the densification behavior in the equiatomic CoCrFeMnNi HEA, focused on microstructural analysis and densification behavior for each thermal schedule. By optimizing the sintering behavior with single and double-step heating rates, significant findings reveal that sintering under double-step heating rates leads to marked improvements in densification and microstructural uniformity. Microstructural analyses indicate that the modulated heating rates during sintering crucially affect the segregation of Cr and secondary phase formation. This research highlights the importance of sintering profiles in optimizing the microstructure and properties of HEAs processed through MIM, contributing valuable insights to a refined strategy for the improved microstructure and mechanical strength of HEAs in powder metallurgy. • CoCrFeMnNi high-entropy alloys are fabricated using metal injection molding. • The deceleration of heating rate in specific temperature ranges during sintering leads to stimulated σ phase transformation and enhanced sintered density. • The conditions of modulated heating rate have a direct correlation between microstructure and tensile properties of the high-entropy alloys. • The MSC analysis demonstrates the efficiency of densification behavior under modulated heating rates condition. • Fine-tuned sintering profile can optimize microstructure and mechanical property of high-entropy alloy processed by powder metallurgy. [ABSTRACT FROM AUTHOR]

Developing metal additive manufactured (AM) parts with excellent mechanical properties broaden the utilization of AM parts in various industrial applications. Recently, gradient structures have received significant attention owing to their excellent mechanical properties. In this study, we propose a new strategy to obtain a superior gradient structure using annealing and ultrasonic nanocrystal surface modification (UNSM) on laser powder bed fusion (LPBF) fabricated 316 L stainless steel. The post-LPBF annealing treatment disturbed the cellular dislocation structure, which led to the optimized materials for gradient structure. The resulting gradient structure after the UNSM treatment has a thicker gradient layer with a significant strain partitioning between the domains than the LPBF followed by UNSM without annealing. As a result, the present LPBF-annealing-UNSM alloys show superior strength-ductility synergy compared to the LPBF-UNSM samples. [Display omitted] [ABSTRACT FROM AUTHOR]