Showing papers by "Halina Garbacz published in 2008"

Surface engineering techniques used for improving the mechanical and tribological properties of the Ti6A14V alloy

Abstract: The microstructure, mechanical and tribological properties of composite intermetallic layers of the Ti–Al system were investigated. The layers on the two-phase (α + β) Ti6Al4V titanium alloy were obtained using the hybrid method, which consist of two stages. First, the titanium alloy was covered with aluminum layer by magnetron sputtering. In the second stage, coated specimens were treated under glow discharge conditions. The surface treatment makes it possible to obtain the diffusional composite layers which considerably improve the mechanical and wear resistance properties of the material. These properties cannot be achieved using simple methods of surface engineering. The chemical and phase composition of the composite intermetallic layers was investigated. It has been shown that the hybrid method significantly increases the hardness and wear resistance of the titanium alloy and can widen the range of application of the material. Because of the diffusional character of the intermetallic layers they possess good adhesion to the titanium substrate.

Nanocrystalline Titanium Rods Processed by Hydrostatic Extrusion

Abstract: The potential application range of coarse-grained commercial purity titanium is limited by its low mechanical properties. A reduction of the grain size of titanium leads to a significant increase in its strength and hardness. This paper is concerned with application of hydrostatic extrusion (HE) for fabrication nano-grained titanium. In the present study titanium rods were subjected to hydrostatic extrusion with the aim to reduce the grain size to the nano-metric scale and thereby improve the mechanical properties. The obtained material can be an equivalent and compete with the commonly used Ti6Al4V alloy. The results were compared with those other SPD techniques reported in the literature and refered to Hall-Petch relationship.

The Influence of the Initial State on Microstructure and Mechanical Properties of Hydrostatically Extruded Titanium

Abstract: Titanium was subjected to hydrostatic extrusion, a method of producing Severe Plastic Deformation (SPD). The experiments were aimed at refining the microstructure of the titanium in order to improve some of its mechanical properties. The effect of the initial state of titanium on the process of extrusion process and the final product was investigated. The results of these investigations are used to establish the optimum conditions for the hydrostatic extrusion process and more easily selecting the initial condition of the material according to the intended application of the extruded product.

Influence of Hydrostatic Extrusion Parameters on the Microstructure and Mechanical Properties of 6082 Aluminium Alloy

Abstract: The aim of the work was to optimise the Hydrostatic Extrusion, HE, parameters in terms of their influence on the microstructure and certain mechanical properties of 6082 aluminium alloy. The investigations focused on the fabrication of a nano- or ultrafine-grained microstructure of the alloy. The effects of a multi-pass process were compared with those of a one-pass process producing the same cumulated true strain of 3.75. Both the multi-pass and the one-pass deformation resulted in profound grain refinement of the alloy. The microstructure contained grains with an average size of 195 nm and 239 nm, respectively. The grain refinement brought about a significant improvement in the microhardness and tensile strength of the alloy. It should be noted that the multi-pass HE produced slightly greater improvement than the single pass process.