This study focuses on numerical prediction and experimental investigation of deformation behaviour of a tungsten heavy alloy prepared via powder metallurgy and subsequent cold (20 °C) and warm (900 °C) rotary swaging. Special emphasis was placed on the prediction of the effects of the applied induction heating. As shown by the results, the predicted material behaviour was in good correlation with the real experiment. The differences in the plastic flow during cold and warm swaging imparted differences in structural development and the occurrence of residual stress. Both the swaged pieces exhibited the presence of residual stress in the peripheries of W agglomerates. However, the NiCO matrix of the warm-swaged piece also exhibited the presence of residual stress, and it also featured regions with increased W content. Testing of mechanical properties revealed the ultimate tensile strength of the swaged pieces to be approximately twice as high as of the sintered piece (860 MPa compared to 1650 MPa and 1828 MPa after warm and cold swaging, respectively).

Knowledge of texture and residual stresses in tungsten heavy pseudoalloys is substantial for the microstructure optimization. These characteristics were determined in cold and warm rotary swaged W/NiCo composite with help of neutron diffraction. The results were discussed in view of the observed microstructure and mechanical properties. The investigated bars consisted of tungsten agglomerates (bcc lattice) surrounded by NiCo-based matrix (fcc lattice). No preferential crystallographic orientation was found in the as-sintered bar. A strong texture was formed in both the tungsten agglomerates ( fiber texture parallel to the swaging axis) and in the NiCo-based matrix ( fiber texture) after rotary swaging. Although usually of double-fiber texture, the fiber of the fcc structures was nearly missing in the matrix. Further, the cold-swaged bar exhibited substantially stronger texture for both phases which corresponds to the higher measured ultimate tensile strength. The residual stress differences were employed for characterization of the stress state of the bars. The largest residual stress difference (≈400 MPa) was found at the center of the bar deformed at room temperature. The hoop stresses were non-symmetrical with respect to the swaging axis, which was likely caused by the elliptical cross section of the as-sintered bar.

Both copper and aluminum are widely applicable throughout a variety of industrial and commercial branches, however, joining them in a composite provides the possibility of combining all their advantageous properties in one material. This study investigates uniquely sequenced copper–aluminum clad composite wires, fabricated via rotary swaging technology. The composites were processed at 20 °C and 250 °C to a diameter of 5 mm. Structural observations and the determination of residual stress within both elements of the swaged wires were performed via electron microscopy; the experimental results were correlated with numerical predictions. As shown in the results, both the applied swaging force and temperature affected the plastic flow, which had a direct influence on residual stress and texture development; the Al_sheath elements exhibited ideal rolling textures, whereas the Cu_wires elements featured ideal shear texture orientation. The grains within both the Al_sheath elements of the 5 mm composite wire were refined down to sub-micron size. Structural restoration also had a positive influence on residual stress.

This study deals with thorough investigation of stress-strain parameters within an innovatively processed tungsten heavy alloy (THA). THAs are challenging materials featuring exceptional mechanical and physical properties and they are applicable in various demanding industrial fields, such as in the aeronautics, medicine, or military. The herein studied material is a WNiCo alloy prepared from original powders via powder metallurgy. The pre-sintered material was processed via plastic deformation, in particular hot rotary swaging with the usage of induction heating directly before a swaging pass. The experimental study was supplemented with numerical simulation of the deformation process, which was performed via the finite element method (FEM). The simulation was primarily focused on prediction of the development of effective imposed strain during the swaging process performed in multiple steps, and its correlation with stress distribution during swaging. The numerically predicted effective imposed strain development was subsequently verified via Vickers microhardness measurements, whereas the predicted results of stress distribution were validated via experimental observation of residual stress distribution performed via analysing scans acquired by scanning electron microscopy (SEM, electron backscatter diffraction analysis). The results showed that the deformation technology consisting of induction heating and hot rotary swaging was well optimized as the swaged billets featured satisfactory surface roughness and no surface cracks. Also, the tungsten agglomerates within the structure exhibited deformation in the direction of the main acting swaging force, especially in the locations the effective imposed strain in which was the highest. The values of predicted effective imposed strain and microhardness correlated reliably with the experimentally acquired and predicted results of residual stress distribution. In other words, the locations the effective strain in which was the highest also exhibited a more significant presence of residual stress.