Khalil Asmaa M, Pozdniakov Andrey V, Solonin Alexey N, Mahmoud Tamer S, Alshah Mohammad, Mosleh Ahmed O
Mechanical Engineering Department, Faculty of Engineering at Shoubra, Benha University, Cairo 11629, Egypt.
Physical Metallurgy of Non-Ferrous Metals, National University of Science and Technology "MISIS", Leninsky Prospekt, 4, Moscow 119049, Russia.
Materials (Basel). 2023 Aug 4;16(15):5477. doi: 10.3390/ma16155477.
This paper studies the effect of the laser melting process (LMP) on the microstructure and hardness of a new modified AlCuMgMn alloy with zirconium (Zr) and Yttrium (Y) elements. Homogenized (480 °C/8 h) alloys were laser-surface-treated at room temperature and a heating platform with in situ heating conditions was used in order to control the formed microstructure by decreasing the solidification rate in the laser-melted zone (LMZ). Modifying the AlCuMgMn alloy with 0.4 wt% Zr and 0.6 wt% Y led to a decrease in grain size by 25% with a uniform grain size distribution in the as-cast state due to the formation of Al(Y, Zr). The homogenization dissolved the nonequilibrium intermetallic phases into the (Al) matrix and spheroidized and fragmentized the equilibrium phase's particles, which led to the solidification of the crack-free LM zone with a nonuniform grain structure. The microstructure in the LMZ was improved by using the in situ heating approach, which decreased the temperature gradient between the BM and the melt pool. Two different microstructures were observed: ultrafine grains at the boundaries of the melted pool due to the extremely high concentration of optimally sized Al(Y, Zr) and fine equiaxed grains at the center of the LMZ. The combination of the presence of ZrY and applying a heating platform during the LMP increased the hardness of the LMZ by 1.14 times more than the hardness of the LMZ of the cast AlCuMgMn alloy.
本文研究了激光熔化工艺（LMP）对一种含锆（Zr）和钇（Y）元素的新型改性AlCuMgMn合金微观结构和硬度的影响。对均匀化处理（480 °C/8 h）的合金在室温下进行激光表面处理，并使用具有原位加热条件的加热平台，以通过降低激光熔化区（LMZ）的凝固速率来控制所形成的微观结构。用0.4 wt% Zr和0.6 wt% Y对AlCuMgMn合金进行改性，由于形成了Al(Y, Zr)，铸态下晶粒尺寸减小了25%，且晶粒尺寸分布均匀。均匀化处理将非平衡金属间相溶解到（Al）基体中，并使平衡相的颗粒球化和破碎，从而实现了无裂纹LM区的凝固，且具有不均匀的晶粒结构。采用原位加热方法改善了LMZ的微观结构，该方法减小了基体与熔池之间的温度梯度。观察到两种不同的微观结构：由于尺寸最佳的Al(Y, Zr)浓度极高，熔池边界处为超细晶粒，而LMZ中心为细小等轴晶粒。ZrY的存在与LMP过程中应用加热平台相结合，使LMZ的硬度比铸态AlCuMgMn合金的LMZ硬度提高了1.14倍。
