Effects Of Different Zr Content And Process On Mg Structure,Performance And Grain Orientation

Magnesium alloys have high specific strength and specific stiffness,and can effectively reduce their weight and improve overall performance in the aerospace field.They are also widely used in the transportation industry.Therefore,the demand for high-performance magnesium alloys in today's society is increasing day by day..Zr is a very effective grain refiner in magnesium alloys.The addition of Zr greatly reduces the grain size of magnesium alloys,thereby improving its comprehensive mechanical properties.Therefore,regarding the smelting process and grain orientation of Mg-Zr alloys And performance impact,we conducted further research.As we all know,the quality of alloy ingots is closely related to the smelting process.In this experiment,Mg-Zr binary alloys with different Zr content gradients were prepared in a vacuum induction furnace,a well-type resistance furnace,and an induction heating furnace,respectively.By means of alloying design and extrusion process,the comprehensive improvement of Mg-Zr alloy strength and plasticity can be achieved to achieve the effect of strengthening and toughening.Through X-ray fluorescence spectroscopic analysis(XRF),metallographic microstructure observation(OM),scanning electron microscope analysis(SEM,EBSD),energy spectrum analysis(EDS),X-ray diffraction analysis(XRD),transmission electron microscope analysis(TEM),As well as tensile and compressive mechanical properties tests,the effects of different Zr contents and processes on the structure,properties and grain orientation of Mg were analyzed.By improving the smelting process,the structure and properties of the alloys cast under different processes were studied.Under vacuum smelting conditions,the smallest grain size of the as-cast alloy can be obtained,followed by the alloy smelted by the induction heating furnace,while the alloy smelted by the traditional well-type resistance furnace shows the largest grain size.In terms of comprehensive mechanical properties,when the Zr content is at a relatively low content(below 1wt.%),Compared with pure magnesium,different ranges of reinforcement and toughness are obtained.Among them,the comprehensive mechanical properties of the alloy obtained by the induction melting process are the best and extend The highest rate is 37.5%,followed by the comprehensive mechanical properties of the alloy obtained by the vacuum melting process,while the comprehensive mechanical properties of the alloy obtained by the well-type resistance furnace melting process are the worst,with an elongation of only5.12%.Through research on the corrosion resistance of alloys with different Zr contents,we found that by comparing the corrosion resistance of pure Mg,when the Zr content is less than 10wt.%,The corrosion resistance of Zr to the substrate has been significantly improved,when the Zr content is 30wt.%Above,Zr has significantly deteriorated the corrosion resistance of the substrate.Through the study of grain orientation,we found that the Mg and Zr two phases with very close lattice constants show a perfectly matched interface relationship when the Zr content is 0.3wt.%,Where(0001)Mg//(0001)?-Zr,mismatch degree ? is 0.618%?(10(?)0)Mg//(10(?)0)?_Zr,mismatch degree?is 0.357%,when Zr content rises to 50wt.%,It shows special The interfacial relationship,in addition to the interfacial relationship shown above when Zr is 0.3wt.%,Also found that the Mg nanocrystals induced around?-Zr are shown as diffraction ring patterns on the Fourier transform diagram,at high The resolution of the transmission image shows that the arrangement of atoms in the nano-region is different from the arrangement of the matrix.