Effect of platform temperature on microstructure and corrosion resistance of selective laser melted Al-Mg-Sc alloy plate

• Published in: Journal of Central South University 2022-03, Vol.29 (3), p.999-1014
• Main Authors: Li, Meng-jia, Lian, Juan, Cao, Ling-fei, Shi, Yun-jia, Zhang, Guo-peng, Wang, Jie-fang, Rometsch, Paul
• Format: Article
• Language: English
• Subjects: Aluminum base alloys; Cooling rate; Copper; Corrosion effects; Corrosion resistance; Engineering; Grain boundaries; Laser beam melting; Magnesium base alloys; Metal plates; Metallic Materials; Microstructure; Phases; Temperature
• ISSN: 2095-2899; 2227-5223
• DOI: 10.1007/s11771-022-4959-z

The Al-3.40Mg-1.08Sc alloy plates were manufactured by selective laser melting (SLM) at platform temperatures of 35 °C and 200 °C, respectively, and the corrosion performance of them was studied along height direction. The results show that the corrosion resistance of the alloy plate built at platform temperature of 35 °C along height direction is basically the same due to a uniform microstructure; While the corrosion resistance of the alloy plate built at platform temperature of 200 °C along height direction is different. The evolution of microstructure and the distribution of secondary phases are investigated, and the results show that the Cu-rich phases in alloy play a key role on corrosion performance. At higher platform temperature, the cooling rate is relative slow and a certain degree of in situ ageing leads to the significantly different distribution of Cu-rich phases along grain boundary. Specimens built at the platform temperature of 200 °C are inclined to locate at the crossed grain boundary, rather than continuous segregation of Cu-rich phases along grain boundary that is built at platform temperature of 35 °C. Therefore, the corrosion resistance of Al-3.40Mg-1.08Sc alloy plate manufactured at platform temperature of 200 °C is higher, and presents a gradually decreasing trend along height direction.