High-entropy alloys have garnered significant attention due to their unique composition and exceptional properties. Additive manufacturing technology, with its distinctive processing methods, offers new options for the fabrication of high-entropy alloys. However, due to the diversity of high-entropy alloys and additive manufacturing technologies, it is imperative to provide a comprehensive overview of the high-entropy alloys produced using various additive manufacturing methods. This paper presents a summary of the microstructure, mechanical properties, and corrosion resistance of high-entropy alloys fabricated using different additive manufacturing techniques. This paper initially reviews the impact of various additive manufacturing process parameters and the influence of different elements on the microstructure of additively manufactured high-entropy alloys. Subsequently, it discusses the effects of different additive manufacturing techniques on mechanical properties and summarizes four strengthening mechanisms in additively manufactured high-entropy alloys. Additionally, the corrosion resistance of various additively manufactured high-entropy alloys is summarized. Finally, based on the review of additively manufactured high entropy alloys presented in this paper, the current challenges and future research directions are proposed.

Aluminum alloy 7075 (with 7055 and 7150 filler wires) was welded using a digital welding machine that can switch arc mode between MIG, CMT and CMT+P modes. The transverse-motion weldability test of joints welded under different arc modes showed that the solidification cracking susceptibility was lower in CMT-technique-based welds than in MIG welds. The temperature cycle of the welding pool under different arc modes was recorded using mini-thermocouples, which showed that the cooling rate was lower in CMT welded samples than in MIG welded samples. The low cooling rate promoted the growth of α-Al dendrites through the back diffusion effect. Electron probe micro-analysis showed that micro-segregation of the α-Al dendrites was lower in the CMT welded samples than in the MIG welded samples. The T-(f_Al)^1/2 curve of each weld was calculated, which showed that CMT-based welding enhanced the bridging of adjacent α-Al dendrites, reducing the tendency for solidification cracking.

In this work, aluminum alloy 7075-T651 was welded by using customized Al-Cu-Si and Al-Cu-Mg-Zn filler wire during gas tungsten arc welding. The liquation cracking susceptibility of the joints was tested under a circular-patch welding experiment. Besides, the temperature vs. solid fraction curves (T-f_S) was calculated for different samples to reveal the formation mechanism of liquation cracking. The joint was susceptible to liquation cracking if (f_S)_weld > (f_S)_workpiece during the cooling stage. The results of the circular-patch welding experiment show that the liquation cracking susceptibility of the joint by using ER5356, Al-Cu_1.5-Si_4.5, Al-Cu_3.0-Si_2.5, Al-Cu_4.5-Si_1.5, Al-Cu_2.3-Mg_2.3-Zn_6.6 and Al-Cu_2.2-Mg_2.0-Zn_7.8 filler metal is 22.8%, 8.3%, 2.8%, 2.8%, 3.3% and 1.4%, respectively. The mechanical test shows that the data dispersion of the 7075 gas tungsten arc welding joint can be decreased by eliminating the liquation crack.