Numerical Investigation on the Strain Evolution of Ti-6Al-4V Alloy during Multi-directional Forging at Elevated Temperatures

Abstract

Multi-directional forging (MDF) is one of the most promising severe plastic deformation (SPD) methods used in fabricating large-scale bulk metal materials with ultra-fine grains (UFG). A finite element model for MDF is developed to investigate the strain evolution of Ti-6Al-4V alloy subjected to MDF. Results show that the billet subjected to MDF can be divided into four individual strain zones in terms of the equivalence of effective strain evolution, and that the strain increment in each individual strain zone varies from pass to pass. The deviation between the maximum and the minimum strain increases with the increase of passes and friction coefficient. The effective strain linearly decreases from the core to the exterior of the billet in all three directions after the MDF process. With the increase of the passes and friction coefficient, the gradient of the effective strain in the billet increases in all three directions due to the difference of deformability in different individual strain zones. For the definite friction coefficient, the average and maximum effective strains are in proportion to the accumulative compression strain.

Analysis of the Multi-Directional Forging of Aluminium Alloy 7075 Process Parameters: Numerical and Experimental Analysis

“…The MDF is a non -linear and multi-axially affected process by the input parameters. Some of the input process parameters identified in the literature include; strain per pass [13,14], frictional conditions at the interface (between the dies and the workpieces) [15], geometry (size and shape) of the workpiece [16], temperature [17][18][19] and die speed [20][21][22]. In this study, the effects of temperature, strain per pass and die speed on the process were studied.…”