Equal channel angular pressing with rotating shear plane to produce hybrid materials with helical architecture of consti
- PDF / 597,755 Bytes
- 8 Pages / 584.957 x 782.986 pts Page_size
- 88 Downloads / 137 Views
Andrey Molotnikov Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia
Alexander Medvedev Institute for Frontier Materials, Deakin University, Waurn Ponds, Victoria 3216, Australia
Yuri Estrin Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia; and Laboratory of Hybrid Nanostructured Materials, National University of Science and Technology “MISIS”, Moscow 119049, Russia (Received 5 June 2017; accepted 31 July 2017)
A modification of the metal processing technique known as equal channel angular pressing (ECAP) to incorporate shear plane rotation, called ECAP-R, is presented. The new process was developed to produce hybrid materials with helical architecture of their constituents, which holds promise to enable enhanced mechanical properties. The process was trialled experimentally using a specially designed laboratory-scale rig. It was shown that a positive mean stress (negative hydrostatic pressure) in a part of the multipiece billet leads to separation of the constituents within that region. A way to improving the process design was suggested based on finite element simulations. It was demonstrated that the proposed processing results in excellent bonding between the helical parts of the hybrid in the regions of positive hydrostatic pressure. Subsequent annealing gave rise to further improvement of the quality of bonding. Processing by ECAP-R at elevated temperatures was suggested as a viable method of producing hybrid materials with helical architecture.
I. INTRODUCTION
Advanced technologies set targets for performance of materials that in many cases are difficult or impossible to meet with conventional materials. Common approaches to improving material characteristics, for example, by alloying or thermomechanical processing, are reaching their limits. In a visionary article about the new ways in design of novel materials, Ashby1 highlighted the potential of hybrid materials, which he defined as combinations of two or more materials whose spatial arrangement adds to the property profile of the resultant material. The material design strategies championed by Ashby1,2 are inspired by geometry and introduce shape and arrangement of the building blocks of hybrids as their new ‘degrees of freedom’.3,4 This geometry aspect defines the hybrid materials as a special case of composites (different from conventional metallic composites produced by traditional methods) with engineered inner architecture.
Contributing Editor: Mathias Göken a) Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2017.339
Relatively recently it was recognized5 that established techniques of severe plastic deformation (SPD) can be used effectively to produce hybrid materials with interesting inner architecture and improved mechanical properties. Indeed, over the past decades SPD processes have advanced to become one of the most potent ways of producing bulk ultrafine-grained materials with exceptional strength
Data Loading...
