Study on Optimization of Parameters Affecting Simple Shear Extrusion of Pure Copper to Fabricate Fine Grain Structure

During last decades, severe plastic deformation (SPD) techniques have developed and increased their applications in variety of industries such as aerospace, nuclear, automotive, marine etc. One of emerging SPD process is simple shear extrusion (SSE). In the present study, an attempt was made to optimize parameters affecting SSE process of pure copper namely maximum distortion angle, channel length and ram speed on effective plastic strain and maximum punch force. Firstly, the process was numerically simulated by use of ABAQUS software. Then, the developed finite element model was verified by confirmatory experiment taking into account the punch force. 15 series of simulation runs were implemented incorporating three aforementioned factors within three levels. Then, response surface methodology was used here to correlate relationship between process parameters to forming force and effective strains. Sensitivity analysis was also carried out to find which factor had greatest impact on process quality characteristics. In order to find optimal parameter setting for maximum strain and strain rate as well as minimum punch force, desirability approach was utilized. Results revealed that distortion angle was the most significant factors affecting plastic strain and punch force, while the ram speed had greatest impact on strain rate. The specimens at optimum parameters (i.e. 45A degrees distortion angle, 90 mm channel length and 0.3 mm/s ram speed that resulted in maximum plastic strain) were processed by SSE and mechanical properties and microstructure analysis were studied. It was found from the results that microstructure of the samples were significantly refined by performing SSE at optimum level that resulted in improvement of samples strength and hardness.