Browsing by Author "Mitra, R."

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Effect of mushy state rolling on age-hardening and tensile behavior of Al-4.5Cu alloy and in situ Al-4.5Cu-5TiB2 composite
(2011) Siddhalingeshwar, I.G.; Herbert, M.A.; Chakraborty, M.; Mitra, R.
The effect of mushy state rolling on aging kinetics of stir-cast Al-4.5Cu alloy and in situ Al-4.5Cu-5TiB2 composite and their tensile behavior in solution-treated (495 C) or differently aged (170 C) conditions, has been investigated. As-cast or pre-hot rolled alloy and composite samples were subjected to single or multiple mushy state roll passes to 5% thickness reduction at temperatures for 20% liquid content. Peak-aging times of mushy state rolled composite matrices have been found as ?7.5-10% of that of as-cast alloy. Such enhancement in aging kinetics is attributed to homogeneity in Cu atom distribution as well as increase in matrix dislocation density due to thermal expansion coefficient mismatch between Al and TiB2, matrix grain refinement and particle redistribution, achieved by mushy state rolling. Uniform precipitate distribution in mushy state rolled composite matrices leads to greater peak-age microhardness with higher yield and ultimate tensile strengths than those in as-cast alloy and composite. 2010 Elsevier B.V.
Effect of mushy state rolling on age-hardening and tensile behavior of Al-4.5Cu alloy and in situ Al-4.5Cu-5TiB2 composite
(Elsevier Ltd, 2011) Siddhalingeshwar, I.G.; Herbert, M.A.; Chakraborty, M.; Mitra, R.
The effect of mushy state rolling on aging kinetics of stir-cast Al-4.5Cu alloy and in situ Al-4.5Cu-5TiB2 composite and their tensile behavior in solution-treated (495°C) or differently aged (170°C) conditions, has been investigated. As-cast or pre-hot rolled alloy and composite samples were subjected to single or multiple mushy state roll passes to 5% thickness reduction at temperatures for 20% liquid content. Peak-aging times of mushy state rolled composite matrices have been found as ?7.5-10% of that of as-cast alloy. Such enhancement in aging kinetics is attributed to homogeneity in Cu atom distribution as well as increase in matrix dislocation density due to thermal expansion coefficient mismatch between Al and TiB2, matrix grain refinement and particle redistribution, achieved by mushy state rolling. Uniform precipitate distribution in mushy state rolled composite matrices leads to greater peak-age microhardness with higher yield and ultimate tensile strengths than those in as-cast alloy and composite. © 2010 Elsevier B.V.
Tensile properties of cast and mushy state rolled Al-4 5Cu alloy and in situ Al4 5Cu-5TiB2 composite
(2010) Herbert, M.A.; Das, G.; Maiti, R.; Chakraborty, M.; Mitra, R.
A comparative study has been carried out on tensile properties and failure mechanisms of Al-4 5 wt-%Cu alloy and in situ Al-4 5Cu-5TiB 2 composite in as cast or mushy state rolled conditions. For the alloy, mushy state rolling at temperature for 30 vol.-% nominal liquid content to 2 5% thickness reduction leads to marginally higher strength but poorer ductility, while both these properties worsen significantly on 5% reduction because of grain growth and intergranular solute segregation. Contrarily, mechanical properties of the composite are significantly improved on mushy state rolling at temperatures for 10-30 vol.-% liquid to 2 5-5% reduction. Improvement in mechanical properties of the composite on mushy state rolling is attributed to evolution of globular and finer grains. Examination of fracture surfaces by scanning electron microscope has shown evidence of ductile failure in as cast alloy and in cast or mushy state rolled composite, but that of brittle failure in mushy state rolled alloy. 2010 W. S. Maney & Son Ltd.
Tensile properties of cast and mushy state rolled Al-4·5Cu alloy and in situ Al4·5Cu-5TiB2 composite
(2010) Herbert, M.A.; Das, G.; Maiti, R.; Chakraborty, M.; Mitra, R.
A comparative study has been carried out on tensile properties and failure mechanisms of Al-4·5 wt-%Cu alloy and in situ Al-4·5Cu-5TiB 2 composite in as cast or mushy state rolled conditions. For the alloy, mushy state rolling at temperature for 30 vol.-% nominal liquid content to 2·5% thickness reduction leads to marginally higher strength but poorer ductility, while both these properties worsen significantly on 5% reduction because of grain growth and intergranular solute segregation. Contrarily, mechanical properties of the composite are significantly improved on mushy state rolling at temperatures for 10-30 vol.-% liquid to 2·5-5% reduction. Improvement in mechanical properties of the composite on mushy state rolling is attributed to evolution of globular and finer grains. Examination of fracture surfaces by scanning electron microscope has shown evidence of ductile failure in as cast alloy and in cast or mushy state rolled composite, but that of brittle failure in mushy state rolled alloy. © 2010 W. S. Maney & Son Ltd.