Ultrafine-grained Al-La-Mg-Mn alloy with superior thermal stability and strength-ductility synergy

作者：Zhang, Xinkui; Li, Liejun^*; Wang, Zhi; Peng, Hanlin; Chen, Songjun; Ban, Tao; Gao, Jixiang; Peng, Zhengwu^*

来源：Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing , 2023, 873: 145035.

DOI：10.1016/j.msea.2023.145035

• Al-La-Mg-Mn alloy
• Ultrafine grain structure
• Outstanding thermal stability
• Powder hot-extrusion

Ultrafine-grained (UFG) structures are highly desirable in microstructural design for their substantial improve-ments in strength and ductility; however, they often face challenges such as thermal instability and high manufacturing costs. In this work, powder hot-extrusion was employed as a cost-effective method to fabricate an Al-La-Mg-Mn alloy with a UFG structure (-0.8 mu m). The as-fabricated alloy exhibited a high-volume fraction of bimodal sub-micron intermetallics, with coarse intermetallics (-270 nm) distributed primarily along the grain boundaries and fine ones (<80 nm) in the grain interior. This unique structure cooperatively retarded the grain growth, resulting in a UFG structure with excellent thermal stability. The grain size grew slightly to 1.08 mu m after thermal exposure at 400 <degrees>C for 100 h. Moreover, the UFG structure exhibited an excellent combination of strength and ductility, with yield strength, ultimate tensile strength, and elongation of 365 MPa, 543 MPa, and 13%, respectively. The UFG structure, decorated with bimodally distributed intermetallics, presents a promising microstructural design for UFG-structured alloys with excellent thermal stability and mechanical properties.

• 单位
  广东技术师范学院