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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MgNi_2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。
Ag-0.24Mg-0.29Ni (%, atomic fraction) alloy sheets were prepared by vacuum smelting and twin-roll rolling. The microstructures of the films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) The microstructure and phase composition of Ag-0.24Mg-0.29Ni alloy sheet were observed by transmission electron microscopy (HRTEM), and the morphology and morphology of the second phase were observed. The results show that the micro-Mg dissolves in the Ag matrix to form the Ag-Mg substitutional solid solution. The intragranular dislocation is easy to enrich Mg, Mg and Ag matrix to form the second phase Mg54Ag17 and precipitate, the second phase Mg54Ag17 and Ag matrix presents a total of Lattice or semi-coherent relationship. The enrichment of Mg in the defects affects the extinction of Ag (100) and makes the (100) surface reflect. The trace amounts of Ni dispersedly dispersed in the solid solution of silver and magnesium in granular form and the second phase of MgNi 2 precipitated on the grain boundary all played the roles of grain refinement and dispersion strengthening on the silver matrix. Accumulation of nickel-rich oxygen-containing oxides, the alloy organization is not uniform, the alloy may be the subsequent internal oxidation process and performance adversely affected.