中文摘要：

采用真空熔炼和双辊轧制技术制备了Ag-0.24Mg-0.29Ni（%,原子分数）合金片材,通过X射线衍射（XRD）、扫描电镜（SEM）、透射电镜（TEM）和高分辨透射电镜（HRTEM）对Ag-0.24Mg-0.29Ni合金片材的微观组织及物相构成、第二相的存在形式及形貌分布进行了观察表征和形貌分析。结果表明：微量Mg固溶在Ag基体中形成Ag-Mg代位固溶体;晶内的螺位错处易于富集Mg,Mg与Ag基体形成第二相Mg54Ag17并析出,第二相Mg54Ag17与Ag基体呈现共格或者半共格关系,富集在缺陷处的Mg影响了面心立方结构Ag（100）的消光,使（100）面出现反射。微量Ni以颗粒状弥散分布在银镁固溶体中,在晶界上析出的第二相Mg Ni2化合物,都对银基体起到晶粒细化和弥散强化的作用;在镍偏聚的缺陷区域,易聚集形成富镍含氧的氧化物,使合金的组织不均匀,可能对合金以后的内氧化进程及性能产生不利的影响。

英文摘要：

The phases and microstructures of Ag-0.24Mg-0.29Ni（ % , atom fraction） alloys and the existing form, morphology, distribution of the second phases which were produced by vacuum smelting and rolling were characterized by X-ray diffraction （ XRD）, scanning electron microscopy （SEM）, transmission electron microscope （TEM） and high resolution transmission electron microscopy （ HRTEM ） respectively. The results showed that Mg was solid dissolved in the Ag-Mg solid solution and concentrated in the screw dislocation; Mg and Ag formed second phase Mg54Ag17, Mg affected the extinction of face-centered cubic structure Ag （100） and made the （110） crystal surface reflect. The second phase Mg54Ag17 had coherent or semi-coherent relation with the matrix. Nickel particles which existed as simple substance were distributed homogeneously in Ag-Mg solid solution; MgNi： which existed as second phase was precipitated on the grain boundary. They all had the effect of dispersion strengthening and grain refinement on the matrix. Ni easily formed nickel-oxide in the defect areas. It might have uneven microstructure and cause unfavorable influence on performance and the later process of internal oxidation.