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In this work, the phenomenon of dynamic strain aging in a high carbon steel is studied and different initial microstructures including fine and coarse pearlite structures are considered. Tensile tests at different temperatures and strain rates are performed to evaluate the occurrence of dynamic strain aging and mechanical properties as well as to calculate apparent activation energies for onset and termination of dynamic strain aging. The results show that dynamic strain aging occurs for both microstructures while the initial microstructures alters the activation energies for appearance and termination of this phenomenon. The microstructural studies illustrate that a combination of cementite decomposition and fracture of cementite layers are responsible for occurrence of dynamic strain aging depending on applied strain rate and deformation temperature.

In the present work, the process of equal channel angular pressing of dispersion strengthened Cu-1?1 wt-%Al 2 O 3 containing nanometric alumina particles was investigated by means of mathematical modelling and experimental testing. Through the modelling, deformation parameters such as hydrostatic pressure distribution and strain field were determined, and the effect of deformation path on these parameters was estimated. Equal channel angular pressing as well as mechanical and microstructural evaluations were also conducted to assess mechanical properties, grain structure and void volume fraction after deformation in different routes. The results indicate that distributions of plastic strain and hydrostatic stresses are significantly affected by deformation path route as well as utilised die design. Furthermore, void formation around hard alumina particles may occur in regions with high tensile hydrostatic stresses leading to fracturing during deformation.

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