Ameliorating mechanical properties and reducing anisotropy of as-extruded Mg-1.0Sn-0.5Ca alloy via Al addition.

Effects of Al addition to a Mg–Sn–Ca ternary alloy on its microstructure and tensile properties after extrusion were studied via extrusion of Mg-1.0Sn-0.5Ca- x Al (x ​= ​0, 0.8, 2.4 ​wt%) sheets and analysis of the extruded materials. The results showed that Al addition not only refined the grain size (from 9.8 ​± ​0.7 ​μm to 8.3 ​± ​0.4 ​μm and 7.6 ​± ​0.5 ​μm) but also accelerated the generation of more second phase (from 0.98 to 1.72 and 4.32%). Except for the CaMgSn and Mg 2 Ca in Mg-1.0Sn-0.5Ca alloy, new phase (Mg, Al) 2 Ca appeared after Al addition. The addition of Al into Mg–Sn–Ca alloy induced the textural variation from an initially ED-split double-peaked texture to a weakened texture, i.e., divergent elliptical texture, due to the effect of particle stimulated nucleation. This eventually contributed to the improvement of mechanical anisotropy as well as the higher Hc value and n -value. For the strain hardening behavior when tension along the TD, the prolonged stage Ⅱ of Al-modified alloys was closely connected with the additional TD textural components, accelerating the activation of more basal slip. The decreased θ Ⅲ0 in stage Ⅲ of Al-modified alloys is beneficial to the grain refinement and the emergence of more second phase. [Display omitted] • In conjunction with the SEM photographs, EDS analysis results and simulated solidification path (under the Scheil-Gulliver conditions via using the data from ThermoCalc2016a) reflects that Al addition accelerates the generation of more second phase. • Compared to the only ED-split double-peaked texture of Mg-1.0Sn-0.5Ca alloy, additional TD textural component was generated after Al addition, which predominately due to the PSN effect induced by the formation of more second phase particles (their size >1 ​μm). • Al addition can greatly reduce the mechanical anisotropy of as-extruded Mg–Sn–Ca alloy and accompanied by the higher Hc value and n -value. [ABSTRACT FROM AUTHOR]