Analysis of forming-induced distortion of dissimilar Ti6Al4V/AA1050 laminate made by non-equal channel lateral co-extrusion

Abstract

The aim of this study is to identify ways for controlling forming-induced distortion of a dissimilar Ti6Al4V/AA1050 laminate prepared by a novel non-equal channel lateral co-extrusion process, which is a modified equal-channel angular pressing process (ECAP) and is characterized by stimulant diffusion bonding via a decrease in the activation energy. First, a thermo-mechanical model of non-equal channel lateral co-extrusion based on the DEFORM-3D software was established along with the introduction of modeling technology. Second, the forming-induced distortions of the dissimilar Ti6Al4V/AA1050 laminate were evaluated in terms of all designed extrusion parameters such as the stripping angle, average velocity relative deviation, average temperature relative deviation, and extrusion force. Third, the process optimization for the mitigation of co-extrusion distortions was performed by employing the orthogonal experimental design and signal-to-noise ratio method. Finally, the experimental validation of numerical model was carried out by using the optimal process configuration. The variable analysis of the results indicates that the pre-heating temperature and the ram speed have a considerable effect on forming-induced distortion modes. The influences of process parameters on the average temperature relative deviation are obviously greater than that on the stripping angle and average velocity relative deviation. In addition, the impact of process parameters on the extrusion force is similar to that of the average temperature relative deviation. The experimental forming-induced distortion of the co-extruded laminate is in good agreement with the simulation result. Thus, this work provides an alternative guideline for the manufacture and distortion control of dissimilar bimetal laminates prepared by co-extrusion.