Effect of Li content on microstructure and mechanical property of Mg-xLi-3(Al-Si) alloys
(1. State Key Laboratory of Mechanical Transmission, College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;
2. National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044, China;
3. College of Civil Engineering, Chongqing University, Chongqing 400045, China;
4. Synthesis and Pollution Control Key Laboratory of Sichuan Province, College of Chemistry and Chemical Engineering, China West Normal University, Nanchong 637002, China;
5. Chongqing Research Center for Advanced Materials, Chongqing Academy of Science and Technology, Chongqing 401123, China;
6. School of Mechanical and Mining Engineering, The University of Queensland, Brisbane Qld 4072, Australia)
2. National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044, China;
3. College of Civil Engineering, Chongqing University, Chongqing 400045, China;
4. Synthesis and Pollution Control Key Laboratory of Sichuan Province, College of Chemistry and Chemical Engineering, China West Normal University, Nanchong 637002, China;
5. Chongqing Research Center for Advanced Materials, Chongqing Academy of Science and Technology, Chongqing 401123, China;
6. School of Mechanical and Mining Engineering, The University of Queensland, Brisbane Qld 4072, Australia)
Abstract: Mg-4Li-3(Al-Si), Mg-8Li-3(Al-Si) and Mg-12Li-3(Al-Si) alloys based on the α-Mg, α-Mg+b-Li, b-Li phases, respectively, were produced to investigate the effect of alloying with Al-Si eutectic on the microstructure and mechanical properties of the three alloys. Alloying with the Al-Si eutectic of Mg-xLi (x=4, 8 and 12 wt.%) alloys caused the formation of different types of Al-Li precipitates: Al3Li, AlLi and Li3Al2, respectively. Also, considerable quantities of Mg2Si phase particles were found in the three alloys. The results of tensile tests showed that the Mg-4Li-3(Al-Si) alloy exhibited the highest ultimate tensile strength (UTS) of 249 MPa but the lowest elongation of 6.3%. The Mg-12Li-3(Al-Si) alloy had the highest elongation of 26% but the lowest UTS of 173 MPa. The different mechanical properties were attributed to the different crystal structures of the three alloys and the precipitate with different type, morphology and distribution.
Key words: Mg-Li alloy; Al-Si eutectic; second phase; tensile strength; elongation