• Kurzydłowski, Krzysztof
• Mazur, A.
• Kulczyk, Mariusz
• Pachla, Wacław
• Lewandowska, Małgorzata
• Łojkowski, Witold
• Diduszko, Ryszard
• Garbacz, Halina

Abstract

<p>The goal of the present work is to demonstrate that a bulk, ultra-fine grained microstructure can be obtained by the hydrostatic extrusion process of a 99.5% technical purity of nickel. Deformation with the total true strain of 3.8 was performed at room temperature to a wire 3 mm in diameter. Microstructure was characterized by light microscopy, TEM, XRD and mechanical properties. Hydrostatic extrusion was shown to be an effective method of severe plastic deformation, which allows ultra-fine grained structures to be obtained within the deformed material. After cumulative hydrostatic extrusion, the yield stress tripled, reaching a maximum of 812 MPa with a moderate elongation of 13%. A mean subgrain size of 200 nm was observed, with a considerable diversity in the size of individual grains. For the final passes of hydrostatic extrusion, a slight decrease in the mechanical properties was observed, accompanied with an increase in crystallite size. This is explained in terms of thermal softening processes activated by the heat generated during hydrostatic extrusion.</p>

Topics

• impedance spectroscopy
• polymer
• grain
• nickel
• x-ray diffraction
• transmission electron microscopy
• wire
• hydrostatic extrusion