A Comprehensive Study of Cooling Rate Effects on Diffusion, Microstructural Evolution, and Characterization of Aluminum Alloys

Cooling Rate (CR) definitively influences the microstructure of metallic parts manufactured through various processes. Factors including cooling medium, surface area, thermal conductivity, and temperature control can influence both predicted and unforeseen impacts that then influence the results of mechanical properties. This comprehensive study explores the impact of CRs in diffusion, microstructural development, and the characterization of aluminum alloys and the influence of various manufacturing processes and post-process treatments, and it studies analytical models that can predict their effects. It examines a broad range of CRs encountered in diverse manufacturing methods, such as laser powder bed fusion (LPBF), directed energy deposition (DED), casting, forging, welding, and hot isostatic pressing (HIP). For example, varying CRs might result in different types of solidification and microstructural evolution in aluminum alloys, which thereby influence their mechanical properties during end use. The study further examines the effects of post-process heat treatments, including quenching, annealing, and precipitation hardening, on the microstructure and mechanical properties of aluminum alloys. It discusses numerical and analytical models, which are used to predict and optimize CRs for achieving targeted material characteristics of specific aluminum alloys. Although understanding CR and its effects is crucial, there is a lack of literature on how CR affects alloy properties. This comprehensive review aims to bridge the knowledge gap through a thorough literature review of the impact of CR on microstructure and mechanical properties.