Development of novel Cu-Cr-Nb-Zr alloys with the aid of computational thermodynamics. (15th October 2018)

• Record Type: Journal Article
• Authors: Yang, Ying; Wang, Ling; Snead, Lance; Zinkle, Steven J.
• Is Part Of: Materials & design. Volume 156(2018)
• Page Start: 370
• Page End: 380
• Publication Date: 2018-10-15
• Subjects: Thermodynamic modeling -- Phase equilibrium calculation -- Alloy design -- Cu-Cr-Nb-Zr alloy; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2018.07.003
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Multi-modal precipitate distribution in the microstructure, with coarse precipitates pinning the grain boundaries and finer precipitates strengthening the matrix, is beneficial to suppress grain boundary sliding and dislocation creep, respectively, of structural materials. However, achievement of a multi-modal precipitate distribution remains a challenge in developing creep-resistant advanced Cu alloys while retaining high strength and high conductivity at elevated temperature. This work overcame this challenge with the aid of computational thermodynamics. Thermodynamic models for Gibbs energy functions of phases in the Cu-Cr-Nb-Zr system have been developed in this study. These models were then used to calculate solidification paths and phase equilibria at different temperatures, guiding the design of chemical composition and heat treatment parameters of novel copper alloys with a target multi-modal distribution of precipitates. The new alloy, fabricated through traditional ingot metallurgy method, has achieved the desired microstructure as validated by optical and transmission electron microscopy. Electrical conductivity and mechanical properties were screened and compared with the existing commercial Cu alloys. Graphical abstract: Unlabelled Image Highlights: Novel Cu-based creep-resistant alloys were designed with the aid of computational thermodynamics. The new Cu alloys were fabricated using an economic ingot-making method. Multi-modal precipitate distribution with larger ones at grain boundaries or dislocations and smaller ones in the matrix have been produced in the microstructure of new Cu alloys.