In the present work, effects of loading scheme and strain reversal on structure evolution are studied by using high pressure torsion (HPT) and twist extrusion (TE) techniques. High purity aluminum (99.99%) was processed at room temperature up to a total average equivalent strain of ~4.8 by TE and HPT with two deformation modes: monotonic and reversal deformation with a step of 12 ̊ rotation. It ...

determination of the deformation length is one of the first steps in roll forming design. roll forming industries are very interested in explicit simple relationsfor prediction the deformation length without using trail-and-error methods at workshop or time consuming finite element simulations. in this paper, elastic properties and work-hardening behaviour of the strip are considered in additio...

A Cu-Cr composite was processed by severe plastic deformation to investigate the role of interphase boundaries on the grain size reduction mechanisms. The as-deformed material exhibits a grain size of only 20nm. This gives rise to a dramatic increase of the hardness. Some deformation induced Cu super saturated solid solutions were clearly exhibited and it is shown that they decrease the hardnes...

Metal cutting is a severe plastic deformation process involving large strains, high strain rates, and high temperatures. Conventional analysis of the chip formation process is based on bulk material deformation disregarding the inhomogeneous nature of the material microstructure. A series of orthogonal cutting tests of AISI 1045 and 1144 steel were conducted which yielded similar process charac...

the study of nucleation mechanism of new grains during severe plastic deformation of magnesium alloys is of great importance to control the characteristics of final microstructures.  to investigate the role of discontinuous recrystallization, a wrought az31 magnesium alloy was deformed by accumulative back extrusion process at 330 °c.  the obtained microstructures were studied using optical and...

It is well known that when coarse-grained metals undergo severe plastic deformation to be transformed into nano-grained metals, their ductility is reduced. However, there are no ductile fracture criteria developed based on grain refinement. In this paper, we propose a new relationship between ductile fracture and grain refinement during deformation, considering factors besides void nucleation a...

Over the last two decades, many researchers have developed a variety of stainless steel-based medical implant types,taking full advantage of nanostructuring technologies. In this paper the application, fabrication and development of nanostructured stainless steel based materials with new composition for medical implants will be discussed. It is well established that application of severe plasti...

Cyclic plastic deformation introduced by forging with a rotating lower anvil leads to materials with grain size between 20 and 200 nm, depending on various factors. This severe plastic deformation process known as High Pressure Torsion (HPT) can be used for forming nanopowders in order to refine their microstructure. Mechanical properties of such products are given by the amount of plastic defo...

Nanocrystalline nc materials are known to deform via mechanisms not accessible to their coarse-grained counterparts. For example, deformation twins and partial dislocations emitted from grain boundaries have been observed in nc Al and Cu synthesized by severe plastic deformation SPD . This paper further develops an earlier dislocation-based model on the nucleation of deformation twins in nc fac...