Mg-Y-Nd-Zr合金均匀化处理工艺及微观组织的研究

Homogenizing and Microstructure of Mg-Y-Nd-Zr Alloy

对Mg-Y-Nd-Zr合金铸锭在不同温度和时间下进行均匀化处理,采用金相显微镜、X射线衍射和扫描电镜及能谱分析仪对合金不同状态下的微观组织和成分进行观察分析。结果表明,合金基体中的金属间化合物以灰色条块状的富Y相和黑色颗粒状的富Nd相为主;均匀化处理后,合金中的富Y相基本上能够完全分解并扩散到基体中,合金在530和547℃经过不同时间的处理后,富Nd相的分布状态基本上没有变化;合金中存在的大量高熔点稀土化合物相起到了阻碍晶粒长大的作用;547℃×6h可以作为Mg-Y-Nd-Zr合金制定均匀化处理工艺的参照。

In this paper, homogenizing of ingots of Mg-Y-Nd-Zr alloy at different temperatures and times were carried out. Optical microscope, X-ray diffraction （XRD）, scanning electron microscope （SEM） and energy dispersive spectrometer （EDS） were used to observe and analyze microstructure and ingredient of interphase of the alloy. The results indicated that in the alloy the precipitated phases as gray strips in shape mainly were rich in Y phases MgE4Y5 and that as black particle in shape were rich in Nd phases Mg12Nd; After 530 ℃ × 36 h or 547℃ × 6 h treatment, the phases which mainly contained Y element mostly decomposed and diffused into the matrix, while the phases which mainly contained Nd element still kept the distribution no changing. A number of Mg-RE compounds existed in the alloy, which have high thermal stabilities, discouraged the grain size of the alloy from growing. For Mg-Y-Nd-Zr alloys, 547 ℃ × 6 h could be as a reference to design a homogenizing.