The influence of multipass processing by Twist Extrusion (TE) on distribution of mechanical properties by volume in commercially pure (CP) titanium billets is investigated. Experiments show that the mechanical properties are almost homogeneous in the billet cross-section already after the second pass of TE. This can be explained by mixing effect and saturation of properties as well. Warm TE leads to the formation of high strength properties in combination with high plasticity. Ultimate and yield stresses of the billet processed by two cycles of TE increased, in comparison with initial state, by 30% and 60% respectively. The value of the reduction in area remained at the initial value. This fact is indicating a high technological plasticity of the material, i.e. its ability for further shaping by metal forming methods.

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It is shown that preloading of fine-grained copper with a the grain size of 0.5 m by a shock wave of intensity ≈ 25-50 GPa does not lead to changes in its internal microstructure and mechanical properties, and the dislocation density increases only slightly from 1.8 · 10 11 cm −2 in the initial state to (3.1-3.6) · 10 11 cm −2 after shockwave loading. An increase in shock wave intensity to pressures > 55 GPa leads to a decrease in the dislocation density to 2.5 · 10 9 cm −2 , an increase in the grain size to ≈19 µm, the occurrence of microtwins inside the grains, and a reduction in the mechanical properties of fine-grained copper to the level of coarse-crystalline copper.

Annealed oxygen-free and tough-pitch copper samples have been processed by equalchannel angular pressing (ECAP) by route BC. The samples included 8 x 8 mm section pieces and a 40 mm diameter bar. Thermal stability was assessed based on the changes in the standard mechanical properties (conventional yield strength, tensile strength, elongation, proportional elongation and contraction) after annealing at different temperatures for 1 hour. Thermal stability of the same grade of material has been found to be different for different batches and to depend on the structural conditions of deformed material. The zone of thermal stability for copper of the two grades of interest does not depend on the material’s chemical composition.