Effects of Ca,Sr Additions on Properties of Mg-Al Based Alloys

Abstract

Effects of Ca alone and Ca/Sr composite additions on microstructures, die castability, mechanical properties and creep properties of the Mg-Al based alloys are investigated for the purpose of the development of new Mg-Al-Ca-Sr alloy for automotive powertrain applications. Ca addition of more than about 1% to AM50 alloy significantly improves creep resistance but also enhance casting crack tendency. By the addition of approximately 0.2%Sr, such casting cracks are significantly suppressed, and besides creep resistance and mechanical properties increase. The improvement of creep resistance by Sr addition seems to be attributed to the suppression of grain boundary sliding due to the creation of thermally stable Al-Sr compound along the grain boundary and the suppression of discontinuous precipitation of -Mg 17 Al 12 phase.

Effect of Strontium Addition on the Microstructures and Mechanical Properties of Mg-5Al-3Ca Alloys

“…3(c)). According to previous studies, 8,10) as the Sr content increases to 1 mass% in the Mg-Al-Ca alloy, the interdendritic phase changes from the Al 4 Sr lamellar phase to the bulky Mg-Al-Sr ternary phase, which is designated as Al 3 Mg 13 Sr. However, in this study, the bulky phase is not a single phase but an ultrafine structure composed of the lamellar eutectic phases.…”

“…If the Sr/Al ratio is lower than 0.3, the Al 4 Sr is formed; and if the ratio is higher than 0.3, the Al 3 Mg 13 Sr is formed. 9) Nakaura et al 10) reported that the addition of 0.22 mass% Sr to Mg-5Al-1.5Ca alloy significantly improved the creep resistance by forming the thermally stable Al-Sr compound (Mg 4 Al 4 Sr) along the grain boundaries and suppressing discontinuous precipitation of the -phase.…”

Mechanical Properties and Microstructure of Magnesium-Aluminum Based Alloys Containing Strontium

“…Yusuke et al found that Ca addition of more than 1 mass% to AM50 alloy not only significantly improved creep resistance but also enhanced casting crack tendency. 10) By the addition of about 0.2 mass% Sr, the casting cracks could be suppressed significantly. Besides, the creep resistance of the alloys increased.…”

“…[1][2][3][4] Therefore, a lot of ways are being investigated in the world in order to further improve the mechanical properties and processing performances of the magnesium alloys. [5][6][7][8][9][10][11][12][13][14][15][16] Alloying is an important method used by many researchers. In recent years, Mg-Al-Sr alloy system has emerged as potential heat-resistant Mg-alloys.…”

Study of deformation texture in an AZ31 magnesium alloy rolled at wide range of rolling speed and reductions

“…Therefore, manufacturing processes such as rolling and stamping should be performed at elevated temperatures [1,8]. These barriers to the manufacturing process increase the price of magnesium wrought alloy products and limits the use of Mg to castings [9][10]. As a result, many studies have been conducted to improve formability by investigating the effect of manufacturing process.…”