Controlling liquation behavior and solidification cracks by continuous laser melting process of AA-7075 aluminum alloy

•Continuous laser melting of AA7075 standard and modified alloy with Sc + Zr, Ti + B and Fe + Ni was performed.•The microstructure and elemental distribution after continuous laser melting were studied.•Uniform and fine structure with absence of solidification cracks was achieved.•Liquation behavior was decreased after continuous laser melting.•Micro-hardness values of AA7075-ScZr and AA7075-FeNi were higher than the other alloys. Microstructure homogeneity, uniform elements distribution, and good mechanical properties are the main research challenges after the continuous laser melting (CLM) process. Adding modifiers to the AA7075 and selecting the proper process parameters are solvers for this challenge. Thus, this paper studies the effect of the CLM on the microstructure, elements distribution, and the microhardness of AA7075 with different modifier contents. The CLM process was carried out with a 300 V power and 0.1 m/s laser scanning speed. The microstructure and elements distribution of the standard and the modified alloys after the CLM were analyzed. The obtained structure was fine with a uniform distribution of elements in all alloys except modified alloy with Fe + Ni. Microhardness was enhanced after the CLM, and the modified alloys with Fe + Ni and Sc + Zr recorded the highest microhardness values in the laser melted zone (LMZ).