Effect of Mg-Zn-Nd spherical quasicrystals on microstructure and mechanical properties of ZK60 alloy

To improve the strength,toughness,heat-resistance and deformability of magnesium alloy,the microstructure and mechanical properties of ZK60 alloy strengthened by Mg-Zn-Nd spherical quasi-crystal phase (I-phase) particles were investigated.Mg40Zn55Nd5 (i-phase) particles in addition to α-Mg,MgZn phase and MgZn2 phases can be obtained in ZK60-based composites under normal casting condition by the addition of quasi-crystal containing Mg-Zn-Nd master alloy.The experimental results show that the introduction of Mg-Zn-Nd spherical quasicrystal phase into ZK60 alloy makes a great contribution to the refinement of the matrix microstructures and the improvement of mechanical properties.While adding Mg-Zn-Nd spherical quasi-crystal master alloy of 4.0wt.％,the ultimate tensile strength and yield strength of ZK60-based composite at ambient temperature reach their peak values of 256.7 MPa and 150.4 MPa,which were about 17.8％ and 24.1％ higher respectively than those of the ZK60 alloy.The improved mechanical properties are mainly attributed to the pinning effect of the quasi-crystal particles (I-phase)at the grain boundaries.This research results provide a new way for strengthening and toughening of magnesium alloys as well as a new application of Mg-based spherical quasi-crystals.