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The cyclic deformation and fracture characteristics of aluminum alloy 6061 are presented and discussed. The specimens were cyclically deformed using fully reversed tension-compression loading under total strain-amplitude control, over a range of temperatures. The alloy showed evidence of softening to failure at all test temperatures. The degree of softening during fully reversed deformation increased with test temperature. The presence of shearable matrix precipitates results in a microstructure that offers a local decrease in resistance to dislocation movement, causing a progressive loss of strengthening contributions to the matrix. At elevated temperatures, localized oxidation and embrittlement at the grain boundaries are exacerbated by the applied cyclic stress and play an important role in accelerating crack initiation and subsequent crack propagation. The fracture behavior of the alloy is discussed in light of competing influences of intrinsic microstructural effects, deformation characteristics arising from a combination of mechanical and microstructural contributions, cyclic plastic strain amplitude and concomitant response stress, and the test temperature. I

The finite element (FE) analysis on the effect of extrusion process parameter namely, extrusion ratio at different billet temperatures on the plastic strain and strain rate of aluminium matrix composite during hot extrusion process has been dealt. The dynamic explicit FE code in ANSYS 15.0 workbench was used for simulation. The FE analysis was carried out on the SiC reinforced aluminium matrix composites for three extrusion ratios 4:1, 8:1 and 15:1, for the billet temperatures in the range 350 °C -450 °C in steps of 50 °C. The plastic strain and strain rate were found to increase with increase in the extrusion ratio. A minimum strain and strain rate was found to occur at the billet temperature of 450 °C. The silicon carbide particles reinforced aluminium matrix composites were then extruded at the optimised temperature of 450 °C for various extrusion ratios as mentioned above. The effect of extrusion ratio on the microstructure and surface quality of extruded rod was studied.