Exploration and optimization of copper-based alloys incorporating amorphizing elements for heat transfer applications

Abstract

Attaining an amorphous crystalline structure imparts unique properties to certain metallic alloys that are impossible to achieve with conventional crystalline alloys. This current study investigates the amorphization potential of small additions of Zr, Ni, or V in CuTi alloys produced using the melt-spinning technique. The alloys are characterized using X-ray diffraction (XRD), differential thermal analysis (DTA), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM) techniques.The need for filler materials with flexible and adaptable properties for joining the first wall and divertor components of future fusion reactors can be addressed by producing filler ribbons with amorphous structures. The results indicate that a combination of Zr (12 at. %) and Ni (8 at. %), when used as alloying elements with appropriate processing parameters such as a rectangular nozzle of 0.5 × 8.8 mm2 and a linear wheel speed of 30 m/s, can produce an amorphous structure. Only isolated nanocrystalline phases were detected by TEM analysis. As a result, ribbons fabricated under these conditions were several times longer and wider than those made using the CuTi master alloy. More importantly, they exhibit enough flexibility to conform to and cover a simulated pipe of the reactor.Conversely, the addition of V led to the formation of brittle phases. Ribbons fabricated under the optimal conditions were tested as filler materials in W-CuCrZr joints at 960 °C and were microstructurally and mechanically characterized, demonstrating their suitability for the intended application.