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Structural changes of Al-6%Ti alloy after hot extrusion and elevated temperature creep

Al-Badrawy A.Abo El-Nasr, Mohamed Ayad

This paper presents some new findings related to the structural changes of Al-6wt%Ti alloy after hot extrusion and elevated temperature creep. This alloy was fabricated by ingot metallurgy (IM) followed by hot extrusion processes, annealed at 650 C for 48 hrs and then subjected to elevated temperature creep tests at 590 and 620 C. Double shear specimen configuration was used in the creep tests due to its suitability for deformation analysis. Microstructure changes of the alloy under these processes were examined and analyzed in terms of size and aspect ratio of the second phase, Al3Ti intermetallic compound, by using the optical microscopy and image analysis facility. The results of thiswork showed the an improvement in size and redistribution of Al3Ti intermetallic compound after hot extrusion and creep tests. The application of such processes reduced the size and aspect ratio of the large flaky shapeAl3Ti particles to uniformly distributed smaller particles. The creep curves of this alloy have been dominated by the primary creep stage followed by very short steady state stage and no indication of the existence of the tertiary creep stage. The analysis of this improvement was discussed in terms of the particle size and aspect ratio of Al3Ti compound.