Mg-Zn-Zr-RE系镁合金的显微组织

MICROSTRUCTURES IN THE Mg-Zn-Zr-RE SYSTEM ALLOYS

应用于航空工业中的MB15镁合金(Mg,5.0～6.0％Zn,0.5～0.9％Zr)为高强度变形镁合金。为进一步提高此合金的强度而添加稀土元素。本文报导含有Y及混合稀土的Mg-Zn-Zr-RE系合金的相组成及其微观形态的研究结果。 试验用合金的化学成分列于表1。表中MM为混合稀土,其中主要元素La10.76％,Nd17.54％,Gd14.60％,Dy14.09％,Y26.88％,此外还有少量Ce、Pr、Ho、Er等。试样用材为铸锭及挤压型材,后者是铸锭经350℃加热2h后挤压而成。

The phase constitution and microstructural characteristics in the as-cast and extruded Mg-Zn-Zr-RE system alloys have been studied. In the as-cast alloys, except for α-Mg matrix, there are Z ph-ase(Mg3RE2Zn3)and W phase(Mg3RE2Zn3) which are distributed along grain boundaries and Zn2Zr3 phase and ZnZr2 phase which precipitated in the matrix. In the extruded alloys, the dispersion-strengthening phase MgZn(phase)was precipitated both in the matrix and along the sub-grain boundaries in addition to the phases mentioned above.