Influences of Y and Y-Rich Mischmetal Additions on Microstructure and Compressive Properties of As-Cast Al-Mg-Mn Alloy

摘要

The influences of Y and Y-rich mischmetal (Ym) additions on microstructural and compressive properties of as-cast Al-13Mg-0.8Mn alloy prepared by vacuum suction casting were investigated in this study. The average secondary dendrite arm spacing (SDAS) was decreased when adding Y and Ym additions. Moreover, the Al_2Y and Al_2Ym phases formed during the solidification were mainly distributed along the grain boundary. The mechanical results reveal that both Y and Ym additions are effective in increasing the compressive strength and hardness. The values of yield compressive strength, ultimate compressive strength, and Brinell hardness of the as-cast Al-13Mg-0.8Mn-0.8Y alloy are 357 MPa, 510 MPa, and 138, respectively. The improved mechanical properties are mainly attributed to fine SDAS and precipitation strengthening. A typical cleavage fracture mode is observed on the compressive fracture surfaces of the alloys.