A review of laser additive manufacturing (LAM) aluminum alloys: Methods, microstructures and mechanical properties

Laser Additive Manufacturing (LAM) is a promising rapid prototyping technique that is commonly used in aerospace and other areas due to its ability to manufacture complex structures quickly. Aluminum alloys have low density, high specific strength, and superior corrosion resistance, making them suitable for a wide range of applications. However, aluminum alloys have high laser reflectivity and thermal conductivity, easily oxidation and a high tendency for hot fractures and pores, making it difficult to obtain LAMed aluminum alloy. Furthermore, it is important to find an optimized laser processing method to obtain high quality (good microstructure and mechanical properties) LAMed aluminum structure. To address the aforementioned issues, as well as the current research status of LAMed aluminum alloys, this paper summarizes the microstructure and mechanical properties of aluminum alloys fabricated by various LAM technologies. The focus is on process application and technical characterization, as well as the issues of improving cracks and pores through different process parameters and post heat treatment. The text discusses the basic concept of aluminum alloys and the principles of some typical LAM processes. It also reviews recent research progress on microstructural characterization, strengthening mechanism evaluation, post heat treatment processes, and nanoparticle strengthening mechanisms. The aim is to establish a preliminary comprehensive relationship between LAM processes, microstructures, and mechanical properties. Finally, in conclusion, this paper forecasts the future development trends of LAMed aluminum alloys.