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为了提高稀土钇在镁合金中的收得率并改善稀土镁合金的组织,采用扫描电镜、XRD、光学显微镜、ICP光谱仪,研究了直接添加金属钇和添加铸态及挤压态Mg-Y中间合金对镁合金组织及稀土钇收得率的影响。结果显示:用井式坩埚炉熔炼镁合金AZ91D,直接添加Y时,在熔炼温度750℃、60 min内收得率低于50%而且未完全熔解。生成的Al-Y金属间化合物组织粗大,并容易沉降到熔体底部。以铸态及挤压态Mg-Y中间合金加入时,生成的Al-Y金属间化合物组织细小均匀,Y收得率分别为71.3%和78.3%;以铸态中间合金加入时收得率略低于以挤压态中间合金加入时的收得率。其原因是中间合金中的α-Mg基体首先溶解,Mg_(24)Y_5相随之分散到熔体并分解为Mg_2Y;经挤压变形后,Mg_(24)Y_5相被破碎成更为细小的颗粒,加入合金熔体后分解为Mg_2Y,粒径越小沉降速度越缓慢,提高了Y的收得率。
In order to improve the yield of rare earth yttrium in magnesium alloy and improve the microstructure of rare earth magnesium alloy, the effects of direct addition of metal yttrium and addition of as-cast and as-extruded Mg-Y intermediate were investigated by scanning electron microscopy, X-ray diffraction, optical microscope and ICP spectrometer. Effect of Alloys on Magnesium Alloy Structure and Yttrium Ore Yield. The results showed that when the magnesium alloy AZ91D was melted in a pit furnace, the yield was less than 50% at 750 ℃ for 60 min and was not completely melted when Y was added directly. The resulting Al-Y intermetallics are coarsely organized and easily settle to the bottom of the melt. When the as-cast and as-extruded Mg-Y master alloys were added, the resulting Al-Y intermetallic compounds were fine and uniform with Y recovery rates of 71.3% and 78.3%, respectively. The yield of the as-cast master alloys was slightly Lower than the middle alloy squeeze state when the accession rate. The reason is that the α-Mg matrix in the master alloy dissolves first and the Mg_ (24) Y_5 phase disperses into the melt and decomposes into Mg_2Y. After extrusion deformation, the Mg_ (24) Y_5 phase is broken into more finer The particles, after being added into the alloy melt, decompose into Mg_2Y. The smaller the particle size, the slower the settling velocity and the higher the yield of Y.