Wire-arc additive manufacturing (WAAM) is a common metal 3D printing technique that offers several benefits, including the high rate of deposition, cheap price, and efficacy for complex parts. Even though (WAAM) has demonstrated its ability to meet the demands of manufacture components on medium-to-large size made of (Al) for the automotive and other related industries, WAAM cannot currently use as a complete production procedure due to practical issues such as mechanical properties that aren’t matched and the presence of significant residual stresses. the AM technologies offer promising new benefits with the MMCs as a solution for some challenges. This article reviews the MMCs Mixing technique and their critical issues, AM classification, WAAM process with advantages and challenges. also reviews WAAM of some AMCs with different reinforcements and power sources. The results of the study of the influence of reinforcement particles on the structure showed that they were changed grains structure from the columnar dendrite to equiaxial dendrites after the solidification and improves hardness.

The dissimilar welding of aluminum to magnesium is challenging because of the rapid formation of brittle intermetallic compounds (IMC) at the weld interface. An Al-Si coating interlayer was selected to address this problem, based on thermodynamic calculations which predicted that silicon would change the reaction path to avoid formation of the normally observed binary Al-Mg IMC phases (b-Al 3 Mg 2 and c-Al 12 Mg 17 ). Long-term static heat treatments confirmed that a Si-rich coating will preferentially produce the Mg 2 Si phase in competition with the less stable, b-Al 3 Mg 2 and c-Al 12 Mg 17 binary IMC phases, and this reduced the overall reaction layer thickness. However, when an Al-Si clad sheet was tested in a real welding scenario, using the Refill ä friction stir spot welding (FSSW) technique, Mg 2 Si was only produced in very small amounts owing to the much shorter reaction time. Surprisingly, the coating still led to a significant reduction in the IMC reaction layer thickness and the welds exhibited enhanced mechanical performance, with improved strength and fracture energy. This beneficial behavior has been attributed to the softer coating material both reducing the welding temperature and giving rise to the incorporation of Si particles into the reaction layer, which toughened the brittle interfacial IMC phases during crack propagation.

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The brittle intermetallic compound (IMC), -Al 3 Mg 2 , grows very rapidly at the interface during dissimilar welding of Al to Mg. This currently prevents acceptable joints being produced between these two important light alloys. In the present study, the use of Al-alloy inter-layer coatings has been investigated to address this problem, for application to friction welding processes. Thermodynamic principles were employed to aid design of the coatings. Two types of coatings were selected: i) a Si-rich coating, which promoted the slower growing and more stable Mg 2 Si phase; ii) an Al-Zn-rich solid solution coating, which replaced the undesired Al 3 Mg 2 phase with a ternary (Al,Zn) 49 Mg 32 intermetallic compound. In statically annealed diffusion couples both coatings were found to inhibit the growth of Al 3 Mg 2. Refill friction stir spot welding (RFSSW) experiments also showed that both coatings were effective in reducing interfacial reaction and can improve the mechanical properties of Al-Mg dissimilar joints.