The aluminium alloy with chemical conception AlMgSi prepared by PM (powder metallurgy) technology was used. The experiments such as a ring and compression test, ECAR (equal channel angular rolling) for determination of friction coefficient, stress-strain curves and material workability based on analytical methods (Freudenthal, Cockcroft-Latham and normalized Cockcroft-Latham criteria) were performed. Numerical simulations of sample processed by ECAR was carried out by a software Deform 3D with focus on the description of stress, strain fields and workability criteria (Cockcroft-Latham and normalized Cockcroft-Latham). The prediction of fracture formations in a real ECAR sample during processing conditions was also done.Keywords: compression test, powder metallurgy, fracture criteria, ECAR, Deform 3DStop aluminium o składzie chemicznym AlMgSi przygotowano metodą proszkową. Wykonano badania takie jak próba ściskania swobodnego pierścieni i walcowatych, ECAR (wyciskanie w kanale kątowym z walcowaniem) w celu wyznaczenia współczynnika tarcia, krzywych naprężenie-odkształcenie oraz podatności materiału na odkształcenie z użyciem metod analitycznych (kryterium Freudenthal, Cockcroft-Latham i znormalizowane Cockcroft-Latham). Symulacje numeryczne dla próbki poddawanej procesowi ECAR przeprowadzono przy pomocy oprogramowania Deform 3D z naciskiem na opis pól sił i naprężeń oraz kryteriów obrabialności (Cockcroft-Latham i znormalizowane Cockcroft-Latham). Przeprowadzono również symulację możliwości tworzenia się pęknięć w rzeczywistej próbce poddanej procesowi ECAR.

The influence of severe plastic deformation (SPD) on distribution of effective stresses, effective strains and temperatures during equal channel angular rolling (ECAR) process is mathematically simulated. Effect of ECAR processing on substructural and mechanical properties of oxygen free high conductivity (OFHC) Cu material is investigated too. Mathematical simulations in software DEFORM-3D, ECAR technology, tensile tests, EBSD analysis were used as experimental methods. Mathematical simulations of first ECAR pass referred on following results: effective normal stress had low heterogeneity with value 385 MPa, effective strain was distinguished with high heterogeneity in cross section of sample (φ=1,5-3) and temperature in deformation zone achieved value 150 °C. Mechanical properties after cold drawing were: Rp0,2 = 217 MPa, Rm = 260 MPa, Z = 63 % and after sixth ECAR pass were: Rp0,2 = 412 MPa, Rm = 426 MPa, Z = 72 %. From experiments is resulting the stabilization of mechanical properties after fourth ECAR pass were obtained.

Non grain oriented isotropic electrical steels, commercially called NGOES, were investigated in cryogenic temperature conditions. At cryogenic temperatures plastic deformations form strong structural heterogeneities in the sample thickness. Samples processed by cryo rolling show a bigger storage energy. To achieve abnormal grain growth through the process of static recrystallization, the annealing conditions were applied to the deformed samples. Moreover, minimal magnetic losses were reached when mean grain size diameter was approximately 150 µm.

The influence of thermo-plastic processes through methods of severe plastic deformations (SPD) and rolling carried out at ambient and cryogenic temperatures on recovery of two materials was investigated. The aim of this study was to insert strains to materials having middle and high stacking fault energy (SFE) in ambient and cryogenic temperature conditions, respectively and subsequently, through DSC method, to observe an influence of the storage energy on structural recovery of materials. As experimental materials were used oxygen free high conductivity copper (OFHC Cu) and C-Si steel which represent materials with middle and high stacking fault energy (SFE), respectively. The OFHC Cu was subjected to equal channel angular rolling (ECAR) by seven passes. ECAR is a method belonging to a SPD group. It was shown, five ECAR passes have a significant effect on material properties. The rolling performed at cryogenic temperatures using a laboratory duo rolling mill was carried out only once. This study implies that a recovery process (characterized by the mobility of structural defects) starts as follows: for OFHC Cu without ECAR and processed by 5thECAR passes: 0.31·Tmeltand 0.19·Tmelt, respectively, for C-Si steel processed by cryorolling: 0.095·Tmelt.

The determination of ductile fracture criteria as well as friction coefficient, stress-strain curves, constants for Hollomon's equation and a material workability based on analytical methods as a forming limit diagram, a normalized Cockcroft-Latham criteria (nCL)) ring and compression tests for two materials based on aluminum and copper alloys were carried out. A calculation of nCL criteria on the basis of a compression test and numerical simulations was made. The critical values nCL criteria resulting from compression test were determined. Prediction of nCL criteria by numerical simulations were confirmed by laboratory compression tests. The values obtained from numerical simulations and compression tests for both materials show a good coincidence in results.