A process model for friction stir welding of age hardening aluminum alloys

Abstract

In the present investigation, a numerical three-dimensional (3-D) heat flow model for friction stir welding (FSW) has been developed, based on the method of finite differences. The algorithm, which is implemented in MATLAB 5.2, is provided with a separate module for calculation of the microstructure evolution and the resulting hardness distribution. The process model is validated by comparison with in-situ thermocouple measurements and experimental hardness profiles measured at specific time intervals after welding to unravel the strength recovery during natural aging. Furthermore, the grain structure within the plastically deformed region of the as-welded materials has been characterized by means of the electron backscattered diffraction (EBSD) technique in the scanning electron microscope (SEM). Some practical applications of the process model are described toward the end of the article.

A numerical comparison of the flow behaviour in Friction Stir Welding (FSW) using unworn and worn tool geometries

“…It is known that the stirring action caused by the tool rotation produces the characteristic shape of the MAZ [35] and that at a distance away from the tool surface there is a lack of plastic deformation. Kim et al [36] reported that a lack of plastic flow occurred during compression testing of Al 7050 at viscosities in the range 10 5 to 10 6 Pa s.…”

Grain Growth Behaviors in a Friction-Stir-Welded ZK60 Magnesium Alloy

“…[2][3][4][5][6][7][8] Grain coarsening often initiates at peripheral regions around stirred zone (SZ) of FSWed material, 2,3,5) and the size of abnormal coarse grains can vary significantly across SZ. 2,6) Development of these grains was heavily influenced by onion rings structure [2][3][4]6) and the growth front was macroscopically uniform though it had some fluctuation in microscopic point of view.…”

Microstructures and Mechanical Properties of Double-Friction Stir Welded 2219 Al Alloy

“…12) Moreover, much finer grains in double-FSW joints were in more unstable state in view of energy contained in microstructure, which offered much bigger driving force for grain growth than in single FSW joints. 13,14) The other reason was the particle density. The relatively accelerated dissolution of fine precipitates in double-FSW joint made density of fine precipitates decreasing as shown in Fig.…”