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It is well known that texture and microstructure play a crucial role in determining properties of metallic materials. The evolution of microstructure and texture during deformation and annealing of copper and some copper base alloys have been investigated to some extent. However, the knowledge about the role of the mode of deformation, particularly different variants of rolling deformation, is still very limited for deformation and annealing texture of two-phase copper alloys. Therefore it appeared important to study the influence of deformation path (in the present case, mode of rolling) on texture and microstructure in two-phase copper alloy Cu-40Zn alloy. Hot rolled bar of Cu-40Zn alloy (as-received material) was subjected to unidirectional and cross rolling ( multi-step cross-rolling) at room temperature with strain per pass (true strain) being constant for each step. In multi-step cross-rolling, the rolling direction was altered (rotated by 90°)after each pass. Strains corresponding to rolling reduction of 50% and 80% were given to as-received material through each of the different mode of rolling. In a second route, the as-received material was solution treated at 800°C for 4 hours first and then subjected to rolling in the same manner as above. A piece was cut from each of the as-rolled materials and was subjected to annealing at 560°C for one hour for recrystallization. The bulk textures were determined by measuring the pole figures at the center of the rolled as well as the annealed specimen using X-ray texture goniometer based on Schultz reflection geometry. Three dimensional texture analyses were carried out using the method of orientation distribution function(ODF). Micro-textures and associated microstructural parameters were determined using a Field Emission Gun Scanning Electron Microscope(FEG-SEM) operated at 20KV, equipped with Electron back scattering detector(EBSD). In the experimental material, texture was examined for both the α (fcc) and the β (ordered cubic) phases. In the present investigation, α phase of unidirectional rolled as-received material had Bs {011}<112> orientation as the strongest component whereas for multi-step cross rolled material P(BND) {011}<111> orientation had the maximum intensity, which could be obtained by rotating the Bs orientation and about ND.The texture development of β phase of as-received unidirectional rolled sample could be understood in terms of relaxed constraints Taylor model. The initial texture had a pronounced effect on texture development of α phase for solution treated alloy during deformation. This material exhibited very strong P(BND) {011}<111> orientation for unidirectional as well as for multi-step cross rolling. For cross rolled alloys, this orientation is promoted by two factors simultaneously, (i) initial texture and (ii) special attributes of cross rolling process. The volume fraction of cube oriented grains was very low for all recrystallized samples because of dominance of Bs orientation in the deformation texture plus formation of shear bands in the microstructure. The texture of β phase for unidirectionally rolled solution treated alloy got sharpened on annealing. However, strength of texture decreased with increasing deformation. Grain boundary (and CSL boundary) analyses were carried out with EBSD data. These analyses indicated that all the recrystallized samples had a high number of Σ3 boundaries. The proportion of Σ3 boundaries was higher in multi-step cross-rolled annealed material. The deformed material had higher number fraction of low angle boundary than any other special boundary. Solution treated material had an average grain size of α phase smaller than the as-received material. Another dimension of the present investigation was to characterize the microstructural features in three dimension(3D) in order to examine the morhphology of constituent phases using serial sectioning. In the present work, 3D studies were carried out on the alloy after post deformation annealing. The alignment of serial section images and generation of 3D image out of the stack of 2D images was carried out through standard software. The same was used to measure the suitable 3D microstructural parameters from the 2D sections. Three dimensional microstructural parameters like mean caliper diameter of β particle, number of β particles per unit volume ‘Nv’, surface to volume ratio for β phase particles (α- β interface) ‘Sv’, were calculated. Number of β particle intercepts per unit area ‘NA’ was determined by measuring number of β phase particle in each section. The volume of a β particle as calculated from the caliper diameter using three-dimensional microstructural analysis, which could not get directly determined with conventional two-dimensional microscopy.

Additive Manufacturing (AM) is an innovative manufacturing process which offers near-net shape fabrication of complex components, directly from CAD models, without dies or substantial machining, resulting in a reduction in lead-time, waste, and cost. For example, the buy-to-fly ratio for a titanium component machined from forged billet is typically 10-20:1 compared to 5-7:1 when manufactured by AM. However, the production rates for most AM processes are relatively slow and AM is consequently largely of interest to the aerospace, automotive and biomedical industries. In addition, the solidification conditions in AM with the Ti alloy commonly lead to undesirable coarse columnar primary β grain structures in components. The present research is focused on developing a fundamental understanding of the influence of the processing conditions on microstructure and texture evolution and their resulting effect on the mechanical properties during additive manufacturing with a Ti6Al4V alloy, using three different techniques, namely; 1) Selective laser melting (SLM) process, 2) Electron beam selective melting (EBSM) process and, 3) Wire arc additive manufacturing (WAAM) process. The most important finding in this work was that all the AM processes produced columnar β-grain structures which grow by epitaxial re-growth up through each melted layer. By thermal modelling using TS4D (Thermal Simulation in 4 Dimensions), it has been shown that the melt pool size increased and the cooling rate decreased from SLM to EBSM and to the WAAM process. The prior β grain size also increased with melt pool size from a finer size in the SLM to a moderate size in EBSM and to huge grains in WAAM that can be seen by eye. However, despite the large difference in power density between the processes, they all had similar G/R (thermal gradient/growth rate) ratios, which were predicted to lie in the columnar growth region in the solidification diagram. The EBSM process showed a pronounced local heterogeneity in the microstructure in local transition areas, when there was a change in geometry; for e.g. change in wall thickness, thin to thick capping section, cross-over’s, V-transitions, etc. By reconstruction of the high temperature β microstructure, it has been shown that all the AM platforms showed primary columnar β grains with a <001>β.