In recent years, much progress has been made in the studies of nanostructured Al alloys for advanced structural and functional use associated both with the development of novel routes for the fabrication of bulk nanostructured materials using severe plastic deformation (SPD) techniques and with investigation of fundamental mechanisms leading to improved properties. This review paper discusses new concepts and principles in application of SPD processing to fabricate bulk nanostructured Al alloys with advanced properties. Special emphasis is placed on the relationship between microstructural features, mechanical, chemical, and physical properties, as well as the innovation potential of the SPD-produced nanostructured Al alloys.

Nanostructured aluminium alloys produced by severe plastic deformation: New horizons in development

The sliding wear behaviour of CoCrFeMnNi and AlxCoCrFeNi high entropy alloys at elevated temperatures

Microstructure evolution and mechanical behavior of a binary Al–7Mg alloy processed by equal-channel angular pressing

Mechanical properties of bulk nanocrystalline Al–4Cu alloys with grain sizes from 47 to 105 nm, synthesized by mechanically alloying followed by vacuum hot pressing at different temperatures, were analysed through Hall–Petch relation. Hall–Petch analysis revealed a high frictional stress (170 MPa) and a high positive slope ( 0.13 MPa m ) as compared to pure Al, which has a frictional stress (15–30 MPa) and a slope ( 0.06 – 0.09 MPa m ). From a detailed evaluation of different strengthening mechanisms it is inferred that the Al 2 Cu precipitates and oxide particles are the likely reason for such high values of frictional stress and slope.

On the Hall–Petch relationship in a nanostructured Al–Cu alloy

The low ductility that is consistently associated with bulk nanostructured (NS) materials has been identified as perhaps the single most critical issue that must be resolved before this novel class of materials can be used in a wide variety of applications. Not surprisingly, a number of published studies, published mostly after 2000, identify the issue of low ductility and describe strategies to improve ductility. Details of these strategies were discussed in review papers published by Koch and Ma in 2005 and 2006, respectively. [15,16] In view of continued efforts and recent results, in this paper we describe progress in attempting to address the low ductility of NS materials, after 2006. We first analyze the fundamental reasons for the observed low ductility of bulk NS materials, and summarize early (prior to 2006) attempts to enhance the ductility of bulk NS materials, which often sacrificed the strength. Then, we review recent progress in developing strategies for improving the tensile ductility of bulk NS materials, which involve mainly microstructure modifications, after 2006. Different from early efforts, these new strategies strive to increase the tensile ductility while increasing/maintaining the strength simultaneously. In addition, the influence of tensile testing conditions, including temperature, strain rate, tensile specimen size and geometry, and strain measurement methods, on tensile ductility of NS materials will also be reviewed. Finally, we identify several issues that will require further, in depth analysis in the future.

T. Shanmugasundaram

Papers

High temperature wear in CoCrFeNiCux high entropy alloys: The role of Cu

Development of ultrafine grained high strength Al-Cu alloy by cryorolling

On the Hall–Petch relationship in a nanostructured Al–Cu alloy

Temperature dependence of the strength of fine- and ultrafine-grained materials

Fabrication of AA7005/TiB2-B4C surface composite by friction stir processing: Evaluation of ballistic behaviour