Numerical Simulation of the Donor-Assisted Stir Material for Friction Stir Welding of Aluminum Alloys and Carbon Steel

Abstract

In this research effort, we explore the use of a donor material to help heat workpieces without wearing the tool or adding more heat than necessary to the system. The donor material would typically be a small piece (or pieces) of material, presumably of lower strength than the workpiece but with a comparable melting point. The donor, a sandwich material, is positioned between the tool head and the material to be welded, where the tool initially plunges and heats up in the same manner as the parent material that is intended for welding. The donor material heats up subsequent to tool penetration due to friction and as a result heats up the material beneath it. This preheating technique softens the harder parent material, which helps to minimize tool wear and produce better weld performance. The goal is to investigate the use of the donor material as a preheating technique that minimizes wear and tear on the tool head without negatively impacting the structural properties of the weld. To demonstrate the donor material concept, a combination of Cu-Al, Cu-1045 Carbon steel (CS), and Al-1045 CS sets of donor and parent materials were used in the simulation, in addition to control samples Al-Al and CS-CS. We simulated two thicknesses of donor material 25 and 50% of the parent material thickness, respectively. The simulation suggests that the donor material concept generates phenomenal results by reducing the temperature and axial forces for the friction stir welding of aluminum AA6061 and carbon steel 1045. It also assists downstream during welding, resulting from frictional mechanical work which is converted into stored heat.

A Review of Numerical Simulation and Modeling in High Strain Rate Deformation Processes

“…These methods use a set of scattered nodes and a moving least squares approximation to represent the material behavior without the need for a mesh. They are particularly useful for simulating problems with large deformations and complex material behavior [28].…”

Friction Stir Welding/Processing of Various Metals with Working Tools of Different Materials and Its Peculiarities for Titanium Alloys: A Review

“…Since it is difficult to remove heat from the welding zone, most studies show that an active liquid cooling system is used in welding [353,359,368], which can be combined with the shielding gas supply system in one device (Figure 13) [353,368]. Friction stir welding or processing requires considerably higher axial loads than for welding aluminum alloys [85,368,402,403]. For this reason, tools for friction stir welding must have high values of strength properties at welding or processing temperatures, which can reach more than 1100 (in peak values, 1300), and when introducing powdered copper particles due to the exothermic formation of intermetallides, 1250 degrees Celsius [287].…”

Elastic properties of the non-mixing copper donor assisted material in friction stir welding of aluminum alloys using nanoindentation

“…To mitigate the extreme wear conditions that occur on the tool heads because of FSW steels, some researchers relied more on expensive tool heads such as tungsten carbide, tungsten rhenium alloys, and, more recently, polycrystalline cubic boron nitride (PCBN) tools (Shah and Warke, 2017;Adesina et al, 2018). Other researchers considered heat management alternatives (Mandal et al, 2013;Rice et al, 2014;Maniscalco et al, 2022). Mandal, Rice, Hou, Williamson, and Elmustafa considered a heat management approach that emphasizes recursive plastic heating (RPH).…”

“…As a fundamental mechanism that operates within the FSW region and provides most of the heat needed to sustain the process. Recently, a thorough numerical (Maniscalco et al, 2022) and experimental (Bhukya et al, 2022) investigation was performed to understand the fundamental interface mechanisms that influence interactions between the tool pin, tool shoulder, and surrounding material flow in the workpiece copper donor material-assisted friction stir welding (FSW) of AA6061-T6 alloy. Cu-assisted FSW joints of AA6061-T6 alloy were prepared at a constant tool rotational rate of 1,400 rpm and welding speeds of 1 and 3 mm/s, respectively.…”