A widely used method for hot forming steels and alloys, especially heavy forging, is the process of multistage forging with pauses between stages. The well-known effect which accompanies multistage hot forging is metal plasticity recovery in comparison with monotonic deformation. A method which takes into consideration the recovery of plasticity in pauses between hot deformations of a billet un...

A comprehensive mathematical model of the hot extrusion process for aluminum alloys has been developed and validated. The plasticity module was developed using a commercial finite element package, DEFORM-2D, a transient Lagrangian model which couples the thermal and deformation phenomena. Validation of the model against industrial data indicated that it gave excellent predictions of the pressur...

Equal channel angular Pressing (ECAP) is an innovative technique for developing ultrafine-grained microstructures first developed by Segal et al in 1981 in the former Soviet Union. The ECAP method consists of two channels that intersect at an angle, generally comprised between 90◦ and 135◦ . The deformation is produced by shear as the billet is extruded through the channels. One of the geometri...

The article outlines the results of adaptive fuzzy decision tree development with dynamic structure for automatic process control system of continuous cast billet production. The authors described the structure, mathematical representation as well as adaptation algorithms and structure dynamics.

Fullering process is a type of open die forging. In this research, elongation and maximum sideways spread in final shape of a billet after the first blow of a fullering process are predicted by designing a back propagation multilayer perceptron neural network. Several experiments are conducted using lead as the model material. Billets with three different square cross-sections are used in these...

Equal channel angular pressing (ECAP) is one of the most prominent procedures for achieving ultra-fine grain (UFG) structures among the various severe plastic deformation (SPD) techniques. In this study, the effect of ultrasonic vibration on deformation behavior of commercial pure aluminum in the ECAP process is analyzed successfully using three dimensional (3D) by finite element methods (FEMs)...

In the white-box attack context, i.e., the setting where an implementation of a cryptographic algorithm is executed on an untrusted platform, the adversary has full access to the implementation and its execution environment. In 2002, Chow et al. presented a white-box AES implementation which aims at preventing key-extraction in the white-box attack context. However, in 2004, Billet et al. prese...

Traitor tracing is needed because some users in broadcast encryption system may give out their decryption keys to construct pirate decoders. Many codes based traitor tracing scheme were proposed. However, as stated by Billet and Phan in ICITS 2008, they lack of revocation ability. We provide a generic scheme of codes based traitor tracing with revocation ability, based on ciphertextpolicy attri...

Abstract: Equal channel angular extrusion (ECAE) is a promising technique for production of ultra fine-grain (UFG) materials of few hundred nanometers size. In this research, the grain refinement of aluminium strip is accelerated by sandwiching it between two copper strips and then subjecting the three strips to ECAE process simultaneously. The loosely packed copper-aluminium-copper laminated b...