Atomic-scale insights into precipitates and their interfacial properties in CuCrZr alloys induced by cryogenic treatment

In this study, high-resolution TEM was utilized to provide a detailed characterization of the precipitates in CuCrZr alloys induced by cryogenic treatment. Building on these findings, first-principles computational models were developed to investigate the mechanical properties of various precipitates and their interfacial bonding characteristics with the matrix. The results demonstrated that cryogenic treatment generated two submicron-sized secondary phases in the matrix: pure Cr particles with a BCC structure and Cu5Zr particles with an FCC structure. Additionally, we observed that nano-sized pure Cr particles were dispersed throughout the matrix and exhibited an orientation relationship of (−111) Cu//(0–11) Cr and [0–11] Cu//[−1−1-1] Cr. First-principles calculations revealed that all the above precipitates exhibited higher modulus and hardness compared to the matrix, with Cr particles being particularly notable. Additionally, the adhesion strength of the Cr/Cu interface was exceptional, surpassing that of the fully coherent CuSlab and CuTwin. Furthermore, the analysis of the electronic properties of the interface revealed that the strengthening effect could be attributed to the higher charge density and localized nature of the Cr atoms near the interface. In summary, precipitates with high hardness and strong adhesion to the matrix can more effectively hinder dislocation movement, which is crucial for enhancing the mechanical properties of the alloys.