Effect of the LPSO volume fraction on the microstructure and mechanical properties of Mg–Y2X–ZnX alloys

摘要

The influence of the volume fraction of longperiod\udstacking ordered structure (LPSO) on the microstructure\udand mechanical properties in three extruded\udMg100-3xY2xZnx alloys (x = 0.5, 1 and 1.5 at.%) has been\udstudied. Two structures of LPSO phase coexist in these\udextruded alloys, 18R and 14H. The 18R structure transforms\udto 14H structure gradually in the course of the\udextrusion process. For the three alloys, the grain size in the\udvicinity of LPSO phase particles is refined because of a\udparticle-stimulated nucleation (PSN) mechanism. The\udreinforcing effect of the LPSO phase is active up to 523 K.\udAbove this temperature, grain size effect becomes important.\udAccordingly, MgY1Zn0,5 extruded alloy shows the\udHighest mechanical strength for temperatures greater than\ud523 K.