The main aim of this study is to produce new powder metallurgy (PM) Cu-B 4 C composite electrode (PM/(Cu-B 4 C)) capable of alloying the recast workpiece surface layer during electric discharge machining process with boron and other hard intermetallic phases, which eventually yield high hardness and abrasive wear resistance. The surface characteristics of the workpiece machined with a PM/(Cu-B 4 C) electrode consisted of 20 wt% B 4 C powders were compared with those of solid electrolytic copper (E/Cu) and powder metallurgy pure copper (PM/Cu) electrodes. The workpiece surface hardness, surface abrasive wear resistance, depth of the alloyed surface layer and composition of alloyed layers were used as key parameters in the comparison. The workpiece materials, which were machined with PM/(Cu-B 4 C) electrodes, exhibited significantly higher hardness and abrasive wear resistance than those of machined with the E/Cu and PM/Cu. The main reason was the presence of hard intermetallic phases, such as FeB, B 4 C (formed due to the boron in the electrode) and Fe 3 C in the surface layer. The improvement of the surface hardness achieved for steel workpiece when using PM/(Cu-B 4 C) electrodes was significantly higher than that reported in the literature. Moreover, the machining performance outputs (workpiece material removal rate, electrode wear rate and workpiece average surface roughness (R a )) of the electrodes were also considered in this study.

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The aim of the study is to evaluate the performance of three recent yield criteria namely; BBC2008-8p, Yld2003-8p, Hu2003 through the simulation of the hemispherical, cylindrical and square cup drawing processes by comparing the results with the ones obtained by using the von Mises criterion for the isotropic, kinematic and combined hardening and the Hill'48 criterion. For this purpose, two different sheet materials, SS304 stainless steel and DKP6112 steel, and various punch travels were used in the simulations and experimental phases of this study. The BBC2008-8p, Yld2003-8p and Hu2003 models were implemented to the ABAQUS software through the user material subroutine VUMAT. The thickness strain distributions obtained from the simulations were compared with the experimental results to analyze the validity of the three aforementioned criteria. Compared with the other models, the material behavior in deep drawing cases of this study is better predicted with more recent models, namely BBC2008-8p, Yld2003-8p and Hu2003, which include anisotropy parameters found from uniaxial and biaxial tension tests.

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