In-situ synthesis and characterization of Cu/NbC, Cu/NbC-WxC, and Cu/ WxC nanocomposites via mechanical alloying

In-situ Cu/NbC, Cu/NbC-WxC, and Cu/ WxC nanocomposites were synthesized by mechanical alloying (MA) at room temperature using high-purity premixed Cu(10-x)NbxW (x = 0, 5, 10 at%) elemental powders. The synthesized powders were then consolidated through Equal Channel Angular Pressing at 700 & DEG;C. The mi-crostructure, phase constituent, and hardness of the as-milled and consolidated powders were investigated using scanning and transmission electron microscopy, X-ray diffraction, and microhardness measurements. The 80 h MA resulted in the formation of a Cu/NbC and Cu/NbC-W nanocomposite powder with an average copper matrix crystallite size of 8-11 nm and NbC and W particle sizes mainly less than 100 nm. Refinement of the powders was achieved through cracking at the work-hardened areas in the copper matrix and fracturing of the tungsten and niobium particles. During consolidation, the W converted into W2C and WC phases. Additionally, the Cu matrix crystallite size increased to 41 nm, 43.6 nm, and 65.3 nm for Cu10Nb, Cu5Nb5W, and Cu10W, respectively. While Cu10Nb showed the highest hardness among the as-milled samples, Cu5Nb5W attained the highest hardness value of 462 HV after consolidation, which is due to its smaller Cu matrix crystallite size and finer carbide particles compared to the Cu10Nb and Cu10W alloys and likely due to the synergistic strengthening effect of the NbC and WxC carbide particles. These findings demonstrate the successful synthesis of in-situ Cu-based nanocomposites with tailored microstructures and constituent phases through mechanical alloying. & COPY; 2023 Elsevier B.V. All rights reserved.

Automated summary

In-situ Cu/NbC, Cu/NbC-WxC, and Cu/WxC nanocomposites were fabricated through mechanical alloying and then consolidated through Equal Channel Angular Pressing. The microstructure, phase constituent, and hardness of the powders were investigated. The results showed that the Cu matrix size and carbide particle size were refined, and WC and W2C phases were formed during consolidation. Cu5Nb5W exhibited the highest hardness due to its smaller Cu matrix size and finer carbide particles, indicating the successful synthesis of tailored Cu-based nanocomposites.