Faculty Publications
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Item Fusion boundary microstructure evolution and mechanical properties of cold metal transfer welded dissimilar A5754 and A5083 joint(Elsevier B.V., 2021) Rajeshkumar, R.; Niranjani, V.L.; Devakumaran, K.; Banerjee, K.Fusion boundary microstructure evolution and its effect on tensile properties of cold metal transfer (CMT) welded joint of dissimilar A5754 and A5083 is studied. Non-dendritic equiaxed fine zone (EQZ) is newly evolved and located between PMZ and weld metal zone (WMZ). The Si films are distributed as continuous layers at grain boundaries (GBs) of EQZ, these films are comparatively less and are distributed in a non-continuous manner at GBs of partially melted zone (PMZ). EQZ of A5083 side exhibits finer grains than A5754 side. The narrower EQZ width, finer grains at EQZ, finer dendrites at WMZ interface and larger distribution of secondary phase particles at PMZ and heat affected zone (HAZ) increase strength of A5083 side. © 2020 Elsevier B.V.Item Evolution of non-dendritic equiaxed zone and its influence on mechanical properties of tungsten inert gas welded dissimilar A6061-T6 and A6082-T6 joint(Elsevier B.V., 2021) Rajeshkumar, R.; Niranjani, V.L.; Devakumaran, K.; Banerjee, K.Non-dendritic equiaxed zone (EQZ) evolution and its influence on tensile properties of tungsten inert gas (TIG) welded joint of dissimilar A6061-T6 and A6082-T6 are studied. EQZ is observed in A6061-T6 interface whereas it is completely absent at the A6082-T6 interface. The distribution of fine Si eutectic phases along the grain boundaries (GBs) of EQZ of A6061-T6 interface appearing as discontinuous fine particles but as a continuous layer at most of the dendrite boundaries (DBs) at the center of the weld metal zone (WMZ). The improvement in strength of A6082-T6 interface compared to A6061-T6 interface is mainly attributed to the absence of EQZ in the former interface. © 2021 Elsevier B.V.Item Recrystallisation Characteristics of a Cu-Bearing HSLA Steel Assessed Through High Temperature Compressive Deformation(Defense Scientific Information and Documentation Centre, 2023) Kumar, A.; Prasad, T.V.V.S.V.; Karthik, V.V.; Banerjee, K.; Gopinath, K.; Balamuralikrishnan, R.Dynamic (DRX) operative during deformation and static recrystallisation (SRX) operative after deformation are considered responsible for the changes in microstructure and texture of deformed materials. Especially in the case of advanced steels that are required in the form of plates of various thicknesses, hot rolling is the main manufacturing process during which the steel undergoes DRX under the rolls and SRX between rolling passes/strands. Knowledge on DRX and SRX characteristics of such steels is crucial for optimisation of hot rolling parameters,achieving the desired microstructure and consequently the targeted mechanical properties.In this study, certain key aspects of both dynamic (DRX) and static recrystallisation (SRX) behaviour of aCu-bearing HSLA steel, which was developed at DMRL, have been explored through high temperature deformation studies using Gleeble thermo-mechanical simulator. Through uniaxial compression testing in the austenitic regime, domains of continuous and discontinuous DRX prevalent in the steel were identified and critical parameters for initiation of dynamic recrystallisation viz., critical strain (ec), critical stress (sc), peak stress (sp) and peak strain (ep) were determined as a function of temperature and strain rate. SRX characteristics were assessed through uniaxial double hit compression tests with fixed strain rate and strain per hit but at different temperatures and with different imposed intermediate static recrystallisation (ISRT) times. From the fractional softening data, parameters such as time for 50 % recrystallisation, t0.5, temperature for 50 % recrystallisation, T0.5, and activation energy, QSRX have been estimated.Although the steel exhibited good plastic deformation characteristics, the results suggest that the role of copper in retarding recrystallisation is significant. © 2023, DESIDOC.