Theoretical and experimental studies on fabrication of two-layer aluminum−copper pipe by friction stir additive manufacturing

Abstract

Using a friction stir additive manufacturing (FSAM) process, the fabrication of a two-layer aluminum−copperpipe was studied experimentally and numerically. For this purpose, by presenting a 3D thermo-mechanical model in ABAQUS software, the temperature and strain distributions during the process were studied. The simulation results show that, although the rotational-to-traverse speed ratio with a good approximation can predict the heat input during welding, it is not a precise measure to predict the occurrence of defects in the weld cross-section. There is a good agreement between the predicted and experimental thermal results, and the maximum relative error is 4.1% in estimating the maximum temperature during welding. Due to heat and severe plastic deformationin the stir zone, the aluminum−copper intermetallic compounds (CuAl2 and Cu9Al4) are formed. The maximum hardness in the stir zone is 301.4 HV0.1in sample welded with an overlap of −0.5 mm.The ultimate tensile strength and elongation of the two-layer pipe fabricated by friction stir additive manufacturingare(319.52±2.31) MPa and 19.47%, respectively.