Papers by Keyword: Superplastic Properties

Abstract: In the present investigation friction stir processing (FSP) is carried out using multipass FSP on a 5086 aluminum alloy to modify microstructure and mechanical properties. Two processing conditions P1 and P2 were used, P1 is carried out at constant rotation speed of 1025 rpm and at a traverse speed of 50 mm/min, P2 is carried out at constant rotation speed of 720 rpm and at a traverse speed of 155 mm/min. Inhomogeneous microstructural distribution was observed across the processed zone. EBSD analysis has been done to evaluate the microstructure. Overlapping passes is showing same grain size in the FSPed material. Material processed using P2 processing condition is showing maximum superplastic ductility. The bulk material produced due to multipass FSP seems to be good for superplastic forming applications.

Abstract: The as-cast and hot worked microstructures of the newly developed β-solidifying ingot-metallurgy Ti-45Al-X (Nb,Mo,B) alloy and its superplastic properties in the hot worked condition have been studied. The obtained experimental findings were used for research of superplastic forming and diffusion bonding of sheet products, which were cut out of hot worked preform by spark cutting. It was shown that superplastic forming might be successfully applied to the obtained fine-grained sheet materials. Relatively low bonding temperatures and pressures were found to be sufficient to achieve sound joints in the sheet material.

Abstract: The availability to produce Ti-6Al-4V sheet material with submicron-grained microstructure for superplastic forming (SPF) has been studied. The laboratory scale sheets with an average grain size of 0.3 μm and the commercial size sheets with an average grain size of 0.65 μm were produced by pack rolling manufacturing technique from the forgings with pre-formed submicrocrystalline (SMC) structure. The sheets possessing isotropic mechanical properties in the sheet plane had higher yield strength, ultimate tensile strength. Over the exceptionally low temperature range of 700-750°C the SMC sheets demonstrated enhanced superplastic properties, namely an initial flow stress of 20-25 MPa and elongation more than 600% at the strain rate of 3×10-4/s. The sheet material with SMC structure was characterized by well formability compared to a conventional sheet under low temperature superplastic conditions.