Composition Optimization of Cu–Ti Master Alloys via Thermodynamic‐Guided Solidification Control

Cu–Ti intermediate alloys with different Ti contents (25, 35, 50, and 60 wt.%) were fabricated via vacuum arc remelting. The effects of Ti content on solidification behavior and microstructural evolution were systematically investigated by combining CALPHAD thermodynamic calculations, differential scanning calorimetry analysis, in situ heating experiments, and phase characterization. The results show that, with increasing Ti content, the microstructural morphology exhibits different types of structures, including cellular eutectic, dendritic, and lamellar eutectic, and is accompanied by the presence of primary phase characteristics. Compared with other compositions, the Cu–50Ti alloy lies close to the eutectic region and exhibits a simplified solidification pathway with a single dominant melting response. Its microstructure is characterized by a small amount of primary CuTi ₂ phase and a uniform CuTi  +  CuTi ₂ lamellar eutectic structure. Comparative experiments using different Ti addition methods demonstrated that the optimized near‐eutectic Cu–50Ti master alloy improves compositional controllability during subsequent remelting and provides a practical approach for producing compositionally homogeneous Cu–Ti alloys.