A strong, ductile and in-plane tensile isotropic Mg-0.5Zn-0.5Y-0.15Si alloy

Abstract

Strength ductility tradeoff, strain hardenability and in-plane isotropy under tensile loading are big dilemmas in magnesium alloys. In this study, we have fabricated an extruded low alloyed Mg-0.5Zn-0.5Y-0.15Si alloy. Based on bimodal grain size, strong basal texture, Schmidt factor analysis and precipitates (MgZn2, Mg3Zn6Y and Mg3Zn3Y2), the alloy exhibited high mechanical strength, high elongation to fracture, strain hardenability and excellent in-plane tensile isotropy. The underlying deformation mechanisms for excellent symmetric and high yield strength along extruded and transverse directions were synergistic effects of low Schmidt factor values of basal slip due to intense basal texture (c-axes//ND), pre-induce dislocation, grain boundary strengthening and precipitate strengthening. While, the strain hardenability and high elongation to fracture are the combined effect of the interaction of basal and profuse non-basal dislocation with precipitates, dislocation pileup at grain boundaries, dislocation pileup on stacking faults and the signature of extension and contraction twinning activity.

Keywords

• Low alloying
• Strength ductility tradeoff
• Isotropy
• Precipitates
• Twinning
• <c+a> dislocation