| The Ag-0.2Mg alloy was prepared by a vacuum induction melting method. Its microstructure and mechanical properties were characterized by metallographic microscope, scanning electron microscope, Vickers hardness tester and electronic universal testing machine. The tensile fracture characteristics of the alloy were studied. The results showed that the microstructure consisted of fine equiaxed grains after treatment at less than 550℃. When the treatment temperature was higher than 650℃, there was a fine grain zone on the surface. The sizes of inner grains gradually increased and the oxidation interface moved to the center part. Its hardness and elongation decreased with the increase of internal oxidation temperature, while its strength increasesd with internal oxidation temperature. After oxidation at 650℃ and 750℃, the fracture of fine grain zone was smooth. The internal oxidation structure was intergranular fracture. The non-oxidized structure was quasi cleavage fracture. After oxidation at 750℃, microporous polymerization fracture occured at the end of fracture. At oxidation temperature of 850℃, the fracture was small plane intergranular fracture, and the micro fracture characteristics of different grains and different crystal planes were not consistent. There were MgO clusters in the micro dimples of two crystal faces of the same grain, which were mainly square in shape. The distribution of Mg atoms and MgO clusters on the two planes was different. |
