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Influence of Equal Channel Angular Pressing on mechanical properties and fracture toughness of Al-Zn alloy were studied in present investigation. Samples are successfully processed using the ECAP technique for up to a four passes by using route A. Al-Zn alloys were heated to a solid solution treatment temperature at 550 °C for 2 h prior to ECAP, this treatment introduces the precipitates which were capable of obstructing motions of dislocation and improves the refinement of the grain during ECAP process Finally, artificial aging was performed at a temperature of 190 °C for 0-20 hours with an interval of 2 h and specimens were cooled at room temperature with natural air. Fracture toughness was found experimentally for ECAP processed samples using SE (B) specimens according to ASTM E399 standard. This study revealed the enhancement in mechanical properties such as yield strength, ultimate strength and microhardness after four passes by route A technique. The improvement in the fracture toughness properties of artificially aged ECAP samples can also be due to dislocation strengthening, grain boundary strengthening, and the creation of much finer UFG grains, according to the results. Despite the increased tensile strength after ECAP, the ductility behavior has decreased due to the precipitation of GP zones and dispersion of η, ή, T and E within the Aluminum matrix, Furthermore, scanning electron microscope (SEM) micrographs revealed that ductile fracture with large dimples occurred in the artificial aged samples after the ECAP procedure. [ABSTRACT FROM AUTHOR]

In the present study, Aluminium-7075 alloy is reinforced with nickel-coated short carbon fibres in the form of short fibre. These composites were prepared by stir casting method with 2, 4, 6 and 8 wt.% of nickel-coated carbon fibres. Wear resistance of aluminium alloy and its composites were analysed according to the ASTM standards. The experiments were conducted using pin-on-disc wear test and rig wear test method with different loads. From the wear test, it was found that aluminium composites with 8% nickel-coated carbon fibre rate of wear are minimum. Worn and fractured surfaces of cast aluminium alloy and the developed composites are analysed by SEM. The test results reveal that the wear resistance of the prepared MMCs improves with the addition of carbon fibre. [ABSTRACT FROM AUTHOR]