Meshfree simulation and experimental validation of extreme thermomechanical conditions in friction stir extrusion

Abstract

Friction stir extrusion (FSE) is a novel solid-phase processing technique that consolidates and extrudes metal powders, flakes, chips, or billets into high-performance parts by plastic deformation, which has the potential to save substantial processing time and energy. Currently, most studies on FSE are experimental and only a few numerical models have been developed to explain and predict the complex physics of the process. In this work, a meshfree simulation framework based on smoothed particle hydrodynamics (SPH) was developed for FSE. Unlike traditional grid-based methods, SPH is a Lagrangian particle-based method that can handle severe material deformations, capture moving interfaces and surfaces, and monitor the field variable histories explicitly without complicated tracking schemes. These aspects of SPH make it attractive for the FSE process, where in situ evolution of field variables is difficult to observe experimentally. To this end, a 3-D, fully thermomechanically coupled SPH model was developed to simulate the FSE of aluminum wires. The developed model was thoroughly validated by comparing the numerically predicted material flow, strain, temperature history, and extrusion force with experimental results for a certain set of process parameters. The validated SPH model can serve as an effective tool to predict and better understand the extreme thermomechanical conditions during the FSE process.

Physics-informed machine-learning model of temperature evolution under solid phase processes

“…Extensive modeling has been undertaken for FSW processes, many employing fluid dynamics models but solidbased models have also been used [6][7][8][9][10][11]. More recently as friction stir extrusion (FSE) processes have become better developed more modeling of FSE has also been done [12][13][14][15]. The severe deformation of materials and thermomechanical interaction make modeling FSE and FSW processes difficult.…”

“…Different approaches have been developed to model deformation, temperature and mass flow. For example, smoothed particle hydrodynamics approaches [12,16], have been successful on these difficult problems. However, the simulation time can be on the order of days even when using high performance computing resources [12].…”

“…For example, smoothed particle hydrodynamics approaches [12,16], have been successful on these difficult problems. However, the simulation time can be on the order of days even when using high performance computing resources [12]. Models also require many parameters that are challenging to measure and/or have large uncertainty, which limits the predictive capability of the models.…”

“…However, it is challenging to model heat generation under ShAPE which includes contributions from multiple sources including friction between the tool and the billet as well as plastic deformation [26]. Generally, most of the heat generation during ShAPE and FSW is attributed to plastic deformation mechanisms [12,27]. It is well known that aside from the elastic-plastic properties of materials, a number of factors such as grain size, grain texture, and loading condition also affect the plastic deformation, hence, the heat generation and temperature.…”

Numerical simulation of the extrusion process of viscoplastic materials using a radial point interpolation method

“…Nonetheless, there are some exceptions. For example, the Smoothed Particle-Hydrodynamics (SPH) has already been extensively used to simulate the friction stir extrusion (FSE), a novel solid-phase processing technique that consolidates and extrudes metal powders (and other kinds of raw materials) into high-performance parts (Li et al, 2022a(Li et al, , 2022b, the additive friction stir deposition (AFS-D) (Stubblefield et al, 2021;Stubblefield et al, 2022), the laser fusion additive manufacturing (Russell et al, 2018), the selective laser melting process (Qiu et al, 2021), which uses a laser to heat metal or alloy powders that melt and solidify into metal parts or melt pool simulations in laser powder bed fusion (LPBF) (L€ uthi et al, 2023). This work investigates the advantages of using the Radial Point Interpolation Method (RPIM) (Wang and Liu, 2002) in the simulation of the viscoplastic extrusion process that occurs in the FFF but already eyes the future modelling of the full FFF process using the same meshless method.…”