Mechanical properties contribution via transformation of precipitates regulation, twinning, and non-basal slip systems activated by trace Y addition in a Mg–4Al-1.5La-2.5Ce-0.3Mn alloy

In this work, the Mg-4Al-1.5La-2.5Ce-0.3Mn- x Y ( x =0, 0.05, 0.1, 0.2) (wt.%) alloys were prepared by vacuum induction melting. Room temperature tensile tests were conducted on the alloys with varied Y contents. The results show that the addition of Y element can adjust the content of the precipitates. The alloy containing 0.2 wt.% Y exhibited the optimal mechanical properties, with ultimate tensile strength (UTS), yield strength (YS), and elongation (EL) values of 210 MPa, 98 MPa, and 12.87%, respectively. It is found that the enhancement in the strength of the alloy is attributed to grain refinement strengthening, precipitates strengthening, and solid solution strengthening induced by Y addition. The improvement in alloy plasticity is due to grain refinement and the activation of non-basal slip systems. The activation of non-basal slip systems effectively reduces stress concentration within the alloy, thereby diminishing twin formation. Furthermore, the clustered Al 11 (La, Ce) 3 and Al 10 (Ce, Y) 2 Mn 7 effectively pin twin boundaries, hindering twin growth. This dual mechanism reduces the likelihood of crack initiation within the alloy.