Principles of equal-channel angular pressing as a processing tool for grain refinement

https://www.tcd.ie/Physics/people/Graham.Cross/SF%20Poster%202011/Schuh-ActaMater07-Mechanical%20behaviour%20of%20amorphous%20alloys.pdf

Mechanical behavior of amorphous alloys

Using high-pressure torsion for metal processing: Fundamentals and applications

https://material.karlov.mff.cuni.cz/people/janecek/studenti/FyzMetNano/Estrin_AM61_2013_782.pdf

Extreme grain refinement by severe plastic deformation: A wealth of challenging science

Despite rosy prospects, the use of nanostructured metals and alloys as advanced structural and functional materials has remained controversial until recently. Only in recent years has a breakthrough been outlined in this area, associated both with development of new routes for the fabrication of bulk nanostructured materials and with investigation of the fundamental mechanisms that lead to the new properties of these materials. Although a deep understanding of these mechanisms is still a topic of basic research, pilot commercial products for medicine and microdevices are coming within reach of the market. This progress article discusses new concepts and principles of using severe plastic deformation (SPD) to fabricate bulk nanostructured metals with advanced properties. Special emphasis is laid on the relationship between microstructural features and properties, as well as the first applications of SPD-produced nanomaterials.

Nanostructuring of metals by severe plastic deformation for advanced properties.

In this paper we report a strategy to simultaneously increase the ductility and strength of bulk nanostructured materials. By engineering very small second-phase particles into a nanostructured Al alloy matrix, we were able to more than double its uniform elongation, while further gaining rather than sacrificing its yield strength. The simultaneous enhancement of ductility and strength is due to the increased dislocation accumulation and resistance to dislocation-slip by second-phase particles, respectively. Our strategy is applicable to many nanostructured alloys and composites, and paves a way for their large-scale industrial applications. The material used in this model study is 7075 Al alloy. The alloy was solution-treated to obtain a coarse-grained (CG) solid solution. The CG sample was immediately cryogenically rolled to produce nanostructures with an average grain size of ca. 100 nm (designated as NS sample). The NS sample was then aged at low temperature to introduce very small secondphase particles (designated as NS+P sample). The engineering stress–strain curves of these samples are compared in Figure 1a. The 0.2 % yield strengths (marked by circles) of the CG, NS, and NS+P samples are 145 MPa, 550 MPa, and 615 MPa, respectively. Therefore, the low-temperature aging enhanced the yield strength of the NS sample by 12 %. The uniform elongation (marked by the symbol on the curves in Fig. 1a) was determined by the Considere criterion (Eq. 1) governing the onset of localized deformation [8]

En Ma

Papers

Simultaneously Increasing the Ductility and Strength of Nanostructured Alloys

Mg-based bulk metallic glass composites with plasticity and gigapascal strength

Tough Nanostructured Metals at Cryogenic Temperatures

A new centimeter-diameter Cu-based bulk metallic glass

Mg–Cu–(Y, Nd) pseudo-ternary bulk metallic glasses: The effects of Nd on glass-forming ability and plasticity