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Microstructure characterization of deformed copper by XRD line broadening

100%

Rzychoń T. , Rodak K.

2007

tom Vol. 28, nr 10

605-608

Purpose: The aim of the present study was to determine the changes in microstructure taking place during deformation with methods like compression, compression with oscillatory torsion as well as compression and subsequent compression with oscillatory torsion (combined method). Design/methodology/approach: The study was conducted on M1E grade Cu. Several methods were used in this study, such as: transmission electron microscopy and X-ray diffraction. The X-ray diffraction line profile analysis was applied to determine crystallite size and density of dislocations. Findings: Application of compression and oscillatory torsion without previous compression resulted in decrease of grain size and crystallite size and increase of lattice distortion caused by dislocation compared to the combined method of deformation. In specimen with higher microstrain and smaller grain size a higher fraction of edge dislocations was observed. Research limitations/implications: Obtained results can be useful to modify the process and design deformation parameters. Practical implications: The knowledge of the characteristic features of unconventionally deformed materials will provide the usability of the method employed to produce materials with desired functional properties. Originality/value: Compression with oscillatory compression is a deformation procedure applied to achieve large strains. However there is no studies on evolution of the microstructures during deformation obtained on the way of the methods mentioned above. This paper provides such an information.

Micro- and nano- structural observations of the surface layer of hardened bearing steel.

70%

Barbacki A. , Kozubowski J. A. , Kawalec M.

1998

tom R. XIX, nr 4

978-981

The paper presents the results of TEM and HREM investigations of the surface layer produced in a hardened 1% C, 1.5% Cr steel by dry machining. The investigations have revealed extremly small micro- and nano- grains probably resulting from large plastic deformation accompanied by localised stress-induced martensite to ferrite transformation and dynamic recovery.

Processing and mechanical properties of mechanically alloyed niobum-rich Nb-Al alloys.

61%

Dymek S. , Dollar M. , Leonard K. , Wróbel M.

1998

tom R. XIX, nr 4

1147-1152

Four Nb-Al alloys containing 15%, 18%, 20% and 25% at. Al were successfully processed by mechanical alloying followed by hot pressing. Analysis of X-ray spectra as well as transmission electron microscopy studies revealed the presence of four phases: niobum solid solution (Nbss), NB3Al, Nb2Al and dispersoids of Al2O3. The grain size was estimated to be = 1 micrometre. The improvement in strength of the mechanically alloyed material was due to the refined grain size and oxide dispersion in the microstructure. The alloys exhibited only limited compressive ductility at room temperature but were ductile at 1000 degrees centigrade. The mechanism for creep deformation in the examined Nb-Al alloys is postulated to be dislocation creep through diffusion controlled climb.