Influence Of High Pressure On Mg-10%Zn-21%Y Alloy Solidification Microstructure And Mechanical Properties

The variation of solidification microstructure,phase and mechanical properties of theMg-10%Zn-21%Y high pressure solidification alloy prepared in different pressure(atmospheric pressure,1GPa,2GPa,3GPa) was studied, which provided theexperimental basis of Mg-Zn-Y high pressure solidification research and riches highpressure solidification theory.For solid solution state of Mg-10%Zn-21%Y alloy produced by the solid solutionpressure increasing from1GPa to3GPa, the dendrite arm of α-Mg solid solutionconstantly decrease, and the appearance of14H ternary experienced the changingprocess of thin strip, wide strip, thin strip and fine needle. The phase S was generatedunder the pressure of1GPa, which experienced the transformation from platelet to fineneedle. The content of Zn in α-Mg solid solution increased from0.55%to2.01%, butthe content of Y increased from2.86%to2.94%, then decrease to2.62%.For low degree of superheat Mg-10%Zn-21%Y alloy generated by thesolidification pressure increasing from1GPa to3GPa, mesophase change from the stripto reticular crystal structure, with its content climbing up and then declining. Theappearance of the14H ternary varied from the strip to the reticular crystal structure,with the pressure increasing to1GPa. With the increasing pressure, the14H ternary wasnot observed. The phase S was produced under the pressure of1GPa, whichexperienced the transformation of platelet,wide net,refinement net. With the increase ofpressure to2GPa, the content of Zn in α-Mg solid solution increased from0.55%to1.26%.With the increase of pressure to3GPa,the content of Zn in α-Mg solid solutiondecreased to1.19%.But the content of Y increased from2.86%to3.27%, with theincrease of pressure to2GPa. When the pressure increased to3GPa, the content of Y inα-Mgsolid solutiondecreased to2.78%.For high degree of superheat Mg-10%Zn-21%Y alloy generated by thesolidification pressure increasing from1GPa to3GPa, the dendrite arm of α-Mg solidsolution constantly increased. The appearance of the14H ternary disappeared with theincrease of pressure. The phase S was produced under the pressure of1GPa, whichexperienced the transformation from the petals shape attached to the14H to the tinychip matched with α-Mg solid. With the increase of pressure to2GPa, the content of Znin α-Mg solid solution increased from0.55%to2.66%. When the pressure increased to3GPa, the content of Zn in α-Mg solid solution decreased to1.82%. The content of Yincreased from2.86%to4.63%, with the increase of pressure to2GPa. With thepressure increasing to3GPa, the content of Y in α-Mg solid solution decreased to3.05%.Tensile strength varied from80.8MPa to139.6MPa. The elastic modulus increased from37.1GPa to43GPa. Vickers hardness value reduced from157to83.