Papers by Author: Terry C. Lowe

Abstract: Nanostructured metals hold the potential to significantly augment the product portfolios of the metals industry. This potential is being progressively developed through contributions from the academic community to the underlying science of nanostructuring, increasing development and protection of intellectual property, and the involvement of large corporations. In this paper we review the trends and status of the commercialization of nanostructured metals technology, focusing on metals produced by severe plastic deformation.

Abstract: A new technique of continuous severe plastic deformation (SPD)-processing, i.e. ECAP (equal channel angular pressing)-Conform is applied for the first time to produce long-length rods of commercial purity Ti with ultrafine-grained structure. The paper reports on the results of investigation of the microstructure and mechanical properties of Ti rods processed by ECAPConform and the following wire drawing.

Abstract: Nanostructured titanium (nTi) with essential enhanced strength and fatigue characteristics is an advanced material for dental implant applications. Nano Ti is commercially pure titanium, that was nanostructured by a special technique of severe plastic deformation. It is bio inert, does not contain even potentially toxic or allergenetic additives and has significantly higher specific strength properties than any other titanium applied in dental implants. Cylindrical threaded screw implants Nanoimplant® sized 2.4 mm in diameter and 12 mm in length were made from nTi. It is the first application of nTi dental implant in the world reported. Recently more than 250 successful clinical applications dealing with surgery on the front teeth were carried out. No complications were noticed during the early postoperative period and early loading. Laboratory cytocompatibility tests undertaken so far on mice fibroblast cells have indicated that nanocrystalline Ti surface has a significantly better property for cell colonisation and healing of tissue consequently.

Abstract: Recent research on the fatigue properties of nanostructured metals and alloys has shown that they generally possess superior high cycle fatigue performance due largely to improved resistance to crack initiation. However, this advantage is not consistent for all nanostructured metals, nor does it extend to low cycle fatigue. Since nanostructures are designed and controlled at the approximately the same size scale as the defects that influence crack initiation attention to preexisting nanoscale defects is critical for enhancing fatigue life. This paper builds on the state of knowledge of fatigue in nanostructured metals and proposes an approach to understand and improve fatigue life using existing experimental and computational methods for nanostructure design.

Abstract: This paper studies the effect of combined SPD treatment on microstructure and mechanical properties of semi-products out of CP Ti. The combined processing, consisting of equal-channel angular pressing and further thermomechanical treatment, produced ultrafine-grained rods out of Grade 2 CP Ti with a diameter of 6.5 mm and a length of up to 1 m. It was established that the formation of homogeneous ultrafine-grained structure in Ti rod with α-grain size of about 100 nm allowed to enhance yield stress by 200% in comparison with initial annealed state.

Abstract: This paper investigates microstructures and mechanical properties of the TI-6AL-4V ELI alloy processed by ECAP and extrusion with various morphology of α and β-phase. Preliminary thermal treatment consisted of quenching and further high-temperature ageing. The present work reveals that the decrease of volume fraction of α-phase globular component in the initial billet results in a more homogeneous structure refinement during SPD, lower internal stress, enhancement of microstructure stability and mechanical properties. An ultimate strength of UTS ≥1350 MPa was obtained in the Ti-6Al-4V ELI alloy while maintaining a ductility of δ≥11%.

Abstract: Six years have passed since the international workshop “Investigations and Applications of Severe Plastic Deformation” held 2-8 August 1999 in Moscow, Russia. This workshop focused on severe plastic deformation (SPD) processing to produce bulk nanostructured metals and alloys. Since 1999 the field has expanded from 200 to over 2000 publications that have addressed the microstructures and properties that can be produced by a growing number of SPD techniques. In view of this expansion, the outlook for ongoing development of severely deformed materials is updated. Special attention is given to factors influencing the manufacturing and commercialization of SPD-processed metals, including barriers to their widespread application. Recommendations are made for future SPD research that will facilitate more rapid commercialization of SPD-processed metals and enhance the competitiveness of SPD processing with respect to alternative technologies for producing bulk nanostructured metals.