Integrated Modeling of Process–Microstructure–Property Relations in Friction Stir Additive Manufacturing

Abstract

Friction stir additive manufacturing is a newly developed solid-state additive manufacturing technology. The material in the stirring zone can be re-stirred and reheated, and mechanical properties can be changed along the building direction. An integrated model is developed to investigate the internal relations of process, microstructure and mechanical properties. Moving heat source model is used to simulate the friction stir additive manufacturing process to obtain the temperature histories, which are used in the following microstructural simulations. Monte Carlo method is used for simulation of recrystallization and grain growth. Precipitate evolution model is used for calculation of precipitate size distributions. Mechanical property is then predicted. Experiments are used for validation of the predicted grains and hardness. Results indicate that the average grain sizes on different layers depend on the temperature in stirring and re-stirring processes. With the increase in building height, average grain size is decreased and hardness is increased. The increase in layer thickness can lead to temperature decrease in reheating and re-stirring processes and then lead to the decrease in average grain size and increase of hardness in stir zone.

A Comprehensive Review of Friction Stir Additive Manufacturing (FSAM) of Non-Ferrous Alloys

“…To the best of the author’s knowledge, the effect of variable thickness in the context of FSAM has not yet been practically investigated. Z. Zhang et al [ 69 ] developed integrated models to explore the effect of variable layer thickness on the temperature and microstructure of the build. Three builds with layer thicknesses of 2 mm, 4 mm, and 6 mm, respectively, were investigated using finite element (FE) simulation.…”

“…Zhao Zhang et al [ 69 ] researched the effect of variable layer thickness on the microhardness and strength of Al-6061-T6 numerically and experimentally. Three sets of builds were created, each with multiple layers of thickness 2 mm, 4 mm, and 6 mm.…”

Review on latest trends in friction-based additive manufacturing techniques

“…Compared to the FSW and FSLW methods, the FSAM process has more flexibility in designing the re-heating and re-sintering time, allowing the process to regulate the microstructural characteristics and acquire the appropriate mechanical qualities. 121 Furthermore, if numerous layers are directly positioned for FSLW, the welding connection at the bottom-most layers may fail. 122 Friction stir additive manufacturing comprises a rotating non-consumable tool that is inserted into a set of overlapping sheets or plates which are then friction stir lap welded in a particular direction to obtain the desired part.…”

“…Compared to the FSW and FSLW methods, the FSAM process has more flexibility in designing the re-heating and re-sintering time, allowing the process to regulate the microstructural characteristics and acquire the appropriate mechanical qualities. 121 Furthermore, if numerous layers are directly positioned for FSLW, the welding connection at the bottom-most layers may fail. 122…”

Friction additive manufacturing technology: A state-of-the-art survey

“…34,35 It can control the structure of microstructure through incremental reheating and remixing. 36,37 Process parameters Sharma et al 39 mentioned in a study that appropriate process parameters directly affected the quality of fabricated materials. The process parameters of friction stir AM include rotation speed, welding speed, shape, and size of tool pin.…”