Nanoparticle additions promote outstanding fracture toughness and fatigue strength in a cast Al–Cu alloy. (15th January 2020)

• Record Type: Journal Article
• Authors: Yang, Chenglin; Zhao, Qinglong; Zhang, Zhenjun; Li, Linlin; Tian, Weisi; Liu, Rui; Zhang, Peng; Xu, Yijiang; Li, Yanjun; Zhang, Zhefeng; Jiang, Qichuan; Ritchie, Robert O.
• Is Part Of: Materials & design. Volume 186(2020)
• Publication Date: 2020-01-15
• Subjects: Cast Al alloys -- Fatigue strength -- Fracture toughness -- Nanoparticles; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2019.108221
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Fatigue resistance and fracture toughness are essential to the reliability of castings during service. Reducing microporosity in cast alloys is a crucial issue for improving their fatigue strength and fracture toughness. Here we report a significant reduction in microporosity of a cast aluminum-copper alloy developed using in situ TiC nanoparticle additions coupled with a stir-casting method. The addition of TiC nanoparticles is found to improve the interdendritic feedability of liquid metal and as a result reduces the volume fraction of microporosity by two orders of magnitude compared to a conventionally cast Al–Cu alloy. This method, which is mechanistically associated with a pore-dominated process, acts to significantly improve the fatigue strength, fracture toughness and uniform elongation of the cast Al–Cu alloy to values which, to the best of our knowledge, represent the highest ever achieved for a cast aluminum alloy. Graphical abstract: Image 1 Highlights: A significant porosity reduction is achieved in Al cast alloy through an in-situ nanoparticle master alloy method. This method serves to uniformly add nanoparticles into metal melt and improve the bonding between particles and matrix. The addition of TiC nanoparticles impedes the formation of porosity and thus improves the mechanical property of Al alloy. The fatigue strength, fracture toughness and elongation of the Al alloy are improved to 114 MPa, 55 MPa m 1/2 and 12%. The mechanism of the mechanical property improvement are revealed with the aid of finite element modeling.