Microstructure and Ratcheting Behavior of Additive Manufactured 4043 Aluminum Alloy

In this paper, 4043 aluminum alloy was printed using additive manufacturing (AM) with robot cold metal transfer (CMT) technology. The microstructure and mechanical properties of different parts, including the bottom, middle and upper portions of the printed AM 4043 aluminum alloy, were analyzed. Ratcheting tests were performed using an asymmetric load, and the tensile properties of the pre-ratcheting and un-ratcheted specimens were tested. The results indicate that the dendrites in the middle region are larger than those at the top and bottom regions and that the coarse microstructure associated with the interlayer junction resulted in the decline of the mechanical properties. The tensile strength of the AM specimens is 165 MPa, and the yield strength is 50 MPa. The printed 4043 aluminum alloy exhibits mechanical properties similar to those for conventional cast and welded aluminum alloys. The ratcheting behavior indicates that an increase in the mean stress or stress amplitude leads to an increase in the ratcheting strain, and the accumulation of ratcheting strain causes plastic damage to the materials. Pre-ratcheting behavior causes the tensile and yield strengths to increase compared to the behavior of the un-ratcheted specimens.