Ahmed E. Nassef; A.I. Alateyah; Medhat A. El-Hadek; W. H. El-Garaihy
Abstract
In 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 ...
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In 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.
G. Ashok Kumar; I. Dinaharan; S. J. Vijay; N. Murugan
Abstract
Friction stir processing (FSP) is a novel solid state technique to refine the microstructure of metallic materials. The objective of this work is to apply FSP to change the morphology and distribution of intermetallic particles and achieve property enhancement. AA6061/8wt. % Al3Zr composite was produced ...
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Friction stir processing (FSP) is a novel solid state technique to refine the microstructure of metallic materials. The objective of this work is to apply FSP to change the morphology and distribution of intermetallic particles and achieve property enhancement. AA6061/8wt. % Al3Zr composite was produced by the in situ reaction of molten aluminum and inorganic salt K2ZrF6. Optical and scanning electron micrographs revealed a uniform distribution of needle shape Al3Zr particles in the aluminum matrix. The Al3Zr particles were located in the inter granular spaces. A double pass FSP was carried out using a tool rotational speed of 1200 rpm, processing speed of 50 mm/min and axial force of 8 kN. A tool made of HCHCr steel; oil hardened to 62 HRC, having a hexagonal profile was used. The needle shape Al3Zr particles were fragmented and converted into a spherical shape subsequent to FSP which resulted an increase in the hardness of the composite.
Rashmi mittal; Devendra Singh
Abstract
The wear behaviour of Al-12Si alloy and Al-12Si-Sn/ZrSiO4 composite prepared by spray forming technique has been investigated under dry sliding conditions at different loads and temperatures. The wear rate of spray formed composite was significantly lower than that of as cast Al-12Si alloy. Paricle size ...
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The wear behaviour of Al-12Si alloy and Al-12Si-Sn/ZrSiO4 composite prepared by spray forming technique has been investigated under dry sliding conditions at different loads and temperatures. The wear rate of spray formed composite was significantly lower than that of as cast Al-12Si alloy. Paricle size of ZrSiO4 was varied from 53 to 105 µm and the amount of Sn was taken 5 and 10 %. Smaller particles of ZrSiO4 were able to reduce the wear rate up to more extent as compared to that of bigger particles in the same matrix. On increasing the amount of Sn the wear rate decreases.