Effect of lanthanum-praseodymium-cerium mischmetal on mechanical properties and microstructure of Mg-Al alloys

Abstract

The effects of lanthanum-praseodymium-cerium mischmetal (LPC) on the microstructure and mechanical properties of Mg-Al alloy were investigated. With the addition of LPC, an additional rod-like Al₁₁La₃ phase was deposited in the alloy. LPC greatly improves the tensile strength of cast Mg-Al alloys but negatively affects the elongation of cast alloys above 473 K. Cast alloys are strengthened by both precipitation strengthening and dispersion strengthening at ambient temperature. When the temperature exceeds 473 K, only the dispersion operates as a strengthening mechanism.

Keywords

lanthanum-praseodymium-cerium mischmetal / Mg-alloy / microstructure / mechanical properties

References

[1] Gerald S Cole. Summary of Magnesium Vision 2020: A North American Automotive Strategic Vision for Magnesium[C]. 2007 TMS Annual Meeting: Symposium on Magnesium Technology, Pennsylvania, 2007

[2] Luo A. A. Recent Magnesium Alloy Development for Elevated Temperature Applications[J]. International Materials Reviews, 2004, 49: 13-30.

[3] Lyon P., Syed I., Heaney S. An Aerospace Magnesium Alloy for Sand Cast and Investment Cast Applications[J]. Advanced Engineering Materials, 2007, 9(9): 793-798.

[4] L Pasternak, R Carnahan, R Decker, et al. Semi-solid Production Processing of Magnesium Alloys by Thixomolding[C]. Proceedings of the Second International Conference on the Processing of Semi-solid Alloys and Composites, 1992: 159–169

[5] L Stephen, W D Matthew. Thixomolding of Magnesium Components for Electronic Applications.[C] Proceedings of the 1999 Fourth Annual Conference on Plastics for Portable and Wireless Electronics, 1999: 49–58

[6] Wenwen D., Yangshan S., Xuegang M., . Microstructure and Mechanical Properties of Mg-Al based Alloy with Calcium and Rare Earth Additions[J]. Materials Science and Engineering A, 2003, 356: 1-7.

[7] Yizhen L., Qudong W., Xiaoqin Z., . Effects of Rare Earths on the Microstructure, Properties and Fracture Behavior of Mg-Al Alloys[J]. Materials Science and Engineering A, 1999, 278: 66-76.

[8] Moreno I. P., Nandy T. K., Jones J. W., . Microstructural Stability and Creep of Rare-earth Containing Magnesium Alloys[J]. Scripta Materialia, 2003, 48: 1 029-1 034.

[9] Anyanwu I. A., Gokan Y., Nozawa S., . Development of New Die-castable Mg-Zn-Al-Ca-RE Alloys for High Temperature Applications[J]. Materials Transactions, 2003, 44: 562-570.

[10] Mabuchi M., Chino Y., Shimojima K., . Mechanical Properties of Aged Mg-4Y-3RE Alloy[J]. Materials Science Forum, 2003, 419–422: 479-484.

[11] Avedesian M. M., Baker H. ASM Specialty Handbook: Magnesium and Magnesium Alloys[M], 1999 New York ASM International 79

[12] Avedesian M. M., Baker H. ASM Specialty Handbook: Magnesium and Magnesium Alloys[M], 1999 New York ASM International 27