Effect of Antimony and Ce-Rich Mischmetal Additions on As-Cast Microstructure and Mechanical Properties of AZ91 Alloy

Abstract:

Various amounts of antimony and mischmetal (Ce-rich) were added into AZ91 cast magnesium alloy and the microstructural characteristics of the cast magnesium alloys were studied by optical microscopy, electronic microscopy and X- ray diffraction techniques. Both antimony and mischmetal had grain refinement effect to AZ91 alloy. When they were added together, a further refinement was observed. SEM-EDX and XRD analysis indicated that a plate-shaped phase, Al11RE3, formed at the boundaries of dendritic α-Mg grain. A rod-like Mg3Sb2 compound distributed both within α -Mg dendrites and along grain boundaries. A new spherical particle, ReSb, formed in the magnesium alloy when 0.8wt%RE and 0.4wt%Sb were join added. The individual additions of antimony or mischmetal to AZ91 alloy did not result in a noticeable improvement to its room temperature tensile properties, but when 0.8wt%RE and 0.4wt%Sb were added together, the as-cast tensile properties of the alloy were increased dramatically.

• Periodical: Materials Science Forum (Volumes 488-489)
• Pages: 219-222
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.488-489.219
• Online since: July 2005
• Authors: Zhong Yang, Jian Ping Li, Gao Hong Li, Jueming Yang
• Keywords: Antimony, As-Cast Microstructure, AZ91 Mg Alloy, Rare Earth (RE), Tensile Properties

References

[1] WANG Mao-sheng, WANG Qudong, Hot-tearing susceptibility of Mg-9Al-xZn- yRE alloy, The Chinese Journal of Nonferrous Metals[J], 2003, 13(1): pp.40-45.

[2] Jiří Bursšík, Milan Svoboda , A HREM and Analytical STEM Study of Precipitates in an AZ91 Magnesium Alloy, Microchimica Acta[J], 2002, 139(4): pp.39-42.

DOI: 10.1007/s006040200036

[3] M. Bamber. Structure refinement of cast magnesium alloy, Materials Science and Technology [J], 2001, 17(15): pp.15-31.

[4] Min, Xuegang, Sun, Yangshan, Effects of Ca, Si and RE additions on the microstructure and mechanical properties of AZ91 based alloy, Journal of Southeast University, (Natural Science Edition), v 32, n 3, May, 2002, pp.409-414.

[5] Guangyin, Y., Yangshan, S., Wenjiang, D., Effect of bismuth and antimony additions on the microstructure and mechanical properties of AZ91 magnesium alloy, Materials Science and Engineering A (J ), v 308, n 1-2, Jun 30, 2001, pp.38-44.

DOI: 10.1016/s0921-5093(00)02043-8