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利用扫描电镜背散射电子技术、透射电子显微镜观察及能谱成分分析,研究在400℃时效处理过程中,不同Zn含量对铸态MgGd3Nd0.3Znx(x=0～1.25,at%,下同)系列合金中析出相和长周期堆垛(LPS)结构形成的影响。结果表明:在时效处理过程中,当Zn含量x≤0.62的合金中初生第二相附近的镁基体中析出平衡相β,而初生第二相则相对稳定无明显变化;当Zn含量x≥1.06时,合金镁基体中无β相析出,初生第二相开始瓦解,并在第二相与镁基体间形成一个含有高密度层错和LPS结构的富Zn和稀土元素的过渡区域。通过对不同Zn含量合金中第二相、过渡区以及镁基体中的成分对比分析,探讨高Zn含量Mg-Gd-Nd-Zn合金中LPS结构的形成原因及生长过程。
The effects of different Zn contents on the as-cast MgGd3Nd0.3Znx (x = 0 ~ 1.25, at%, same below) series were investigated by scanning electron microscopy backscattering electron microscopy, transmission electron microscopy and energy spectrum analysis. Alloy precipitation phase and long period stacking (LPS) structure formation. The results show that during the aging treatment, when the content of Zn is less than or equal to 0.62, the equilibrium phase β is precipitated in the magnesium matrix near the primary second phase, whereas the primary phase is relatively stable without any significant change. When the Zn content is x≥1.06 , No β phase is precipitated in the alloy magnesium matrix, the primary second phase begins to disintegrate, and a Zn-rich and rare earth transition region containing high-density layer faults and LPS structure is formed between the second phase and the magnesium matrix. The formation mechanism and growth process of LPS structure in high Zn content Mg-Gd-Nd-Zn alloy were investigated by comparing the composition of the second phase, the transition zone and the magnesium matrix in different Zn content alloys.