Effect Of High Pressure On Solidification Structure And Mechanical Properties Of Mg-17Zn-1Y Alloy

Mg-17Zn-1Y alloy was used as the research object.The microstructure and phase of the alloy were studied by OM,SEM,XRD and EDS.The effects of different pressures(1GPa,2GPa and 3GPa)Alloy in the organization,phase and mechanical properties of the changes in the law,the experimental data and theory for the rich high-pressure solidification theory has a certain significance.The results show that there are ?-Mg,14 H and Mg7Zn3 phases in the Mg-17Zn-1Y alloy after homogenization,Mg7Zn3 is in the form of strips and meshes in the matrix,and the 14 H phase exhibits a strip or lamellar The After the solution of high pressure solution,when the solution pressure is increasing,the 14 H phase changes from the strip,the lamellar to the fine strip and the needle,and the content of Zn in the ?-Mg is 2.44at%;When the solution pressure becomes 1GPa time to2.67at%,and finally from 2.82at% of 2GPa to 3.40at% of 3GPa,and with increase of solution pressure,Y content gradually decreased from 1GPa of 0.28at% becomes0.12at% at 2GPa,and finally decreases to 0.01at% of 3GPa.In the alloyed structure at 1GPa,the Mg-Zn binary phase and ?-Mg form eutectic structure and are staggered to form a network structure.14 H is distributed in the matrix in the matrix,the lamellar or lamellar,While some of the Y-rich phase is distributed in the matrix.When the solidification pressure is increased to 2GPa,the phase composition is still ?-Mg,Mg-Zn binary phase and 14 H,14H phase number is greatly increased,while Mg-Zn binary phase volume fraction increases,part of the network structure broken,At the same time there are still blocks and dot-like Y-rich phase generated.The content of 14 H phase in the solidified alloy structure under the 3Gpa is reduced,most of the network structure disappears,the structure is obviously refined,and the 14 H phase changes from the original slab or lamellar to the fine needle.When the solidification pressure gradually increases,the solubility of Y in ?-Mg decreases from 0.37at% in 1GPa to 0.07at% at 3GPa,and the content of Zn atoms is 2.44at% at atmospheric pressure,,When the pressure increased to 1GPa increased to 2.58at%,then from 2.76at% under 2GPa to 3.89at%under 3GPa.The tensile strength of the alloy was improved from 48.7MPa under normal solidification to 139.6MPa under the solidification at 33?,and the Vickers hardness changed from 113.1HV at 1GPa to 2GPa 132.3HV,and in the 3GPa continued to increase to 134.2HV.