Mechanical behavior and fracture surface characterization of liquid-phase sintered Cu-Sn powder alloys
Advanced Materials Letters,
2017, Volume 8, Issue 6, Pages 717-722
AbstractIn this study, elemental Cu and Sn powder were mechanically mixed forming different Cu-Sn alloys. To ensure uniformity of the particle shapes, the Cu, and Sn were mechanically milled and mixed in an agate rock mortar, with high energy ball mill for half an hour, with different weight ratios according to the composition design. The milling of the powders resulted in uniform sphere-like particles for Cu–Sn alloys. Hot compaction was performed in a single acting piston cylinder arrangement at room temperature. All hot pressed MMCs were heat-treated at about 550°C to allow the atoms to diffuse randomly into a uniform solid solution, as liquid phase sintering. Vickers micro-hardness measurements were carried out for the hot-pressed Cu–Sn alloys. Cylindrical specimens of aspect ratio of ho/do = 1.5 were tested under frictionless conditions at the compression platen interface. Charpy transverse rupture strength had been used to determine the fracture strength of the different Cu-Sn alloys. Fracture surface features of the different Cu-Sn alloys were characterized using scanning electron microscopy. It had been found that, the 85%Cu–15% Sn alloy revealed an increase of hardness values, a decrease of the yield strength, and an increase in the impact energy by 26.2, 23, and 18.7%; respectively, compared with the Sn-free alloy. The Cu-Sn alloys showed an apparently classical inclined fracture surface, at about 45 o with the applied stress axis, which was similar to what’s obtained for a diversity of hard metals.
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