The composition profile and the microstructure formation of unidirectionally solidified Al–4.5 wt% Cu sample was investigated. The thermal analysis technique determined the vertical Bridgman’s test sample solidification parameters. Characterization of microstructures was conducted with an optical microscope, and Image-J software determined the α-Al area. Energy-dispersive X-ray spectroscopy was used to assess the composition. The composition profile was confirmed with the actual density and micro-hardness value. The results show that the composition of Cu varies between 4.93 and 3.99%, along with the 98.3% drop in the cooling rate. The reduction of Cu composition is in line with the α-Al area, actual density, and micro-hardness value. Two different morphologies of eutectics are found, fine internal fragments in 1.12 to 2.4 °C/s (less than 35 mm) and the lamellar in 0.04 to 0.06 °C/s cooling zone (more than 35 mm).

研究了单向凝固的Al–4.5 wt％Cu样品的成分分布和显微组织形成。热分析技术确定了垂直Bridgman的测试样品凝固参数。用光学显微镜对微结构进行表征，并用Image-J软件确定α-Al面积。能量色散X射线光谱法用于评估组成。用实际密度和显微硬度值确认了组成分布。结果表明，Cu的组成在4.93％至3.99％之间变化，冷却速率下降了98.3％。Cu组成的减少与α-Al面积，实际密度和显微硬度值一致。发现了两种不同的共晶形态，在1.12至2中有细小的内部碎片。