Design of a new Al-Cu alloy manipulated by in-situ nanocrystals with superior high temperature tensile properties and its constitutive equation. (5th November 2019)

• Record Type: Journal Article
• Authors: Zhu, Lin; Liu, Tian-Shu; Duan, Tao-Tao; Li, Tao-Tao; Qiu, Feng; Yang, Hong-Yu; Bai, Zhi-Hao; Liu, Ying-Ying; Jiang, Qi-Chuan
• Is Part Of: Materials & design. Volume 181(2019)
• Publication Date: 2019-11-05
• Subjects: In-situ nanocrystals -- Amorphous alloys -- Microstructure refinement -- Mechanical properties -- Precipitates -- Stress prediction model; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2019.107945
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: AlCu alloys inoculated by in-situ nano-sized particles crystallized from Ni-Nb-Ti amorphous alloys were prepared by casting method in this work. Different compositions of Ni-Nb-Ti amorphous alloys significantly enhanced heterogeneous nucleation for α-Al and promoted obvious grain refinement of the AlCu alloys. It was found that 0.05 wt% Ni-Nb-Ti amorphous alloys addition caused a significant and efficient refinement on α-Al (from 200 μm to 39 μm) and θ′ phase (from 146.4 nm to 37.6 nm). The strength and ductility of the inoculated alloy were improved significantly at high temperature. The tensile strength and fracture strain of the alloy inoculated by 0.05 wt% Ni-Nb-Ti amorphous alloy for 20 min at 533 K under the strain rates of 10 −1 s −1 were increased by 32.63% and 90.35% respectively, compared to those of the uninoculated alloy. The nano-sized NiTi particles contributed to the grain refinement of α-Al, and grain refinement shortened the solute atomic diffusion distance and refined θ′ phase during heat treatment, resulting in higher strength and plasticity at high temperature. The model developed for this new type AlCu alloy is found to be efficient in predicting the stress at 453 K–533 K under the strain rates of 10 −4 s −1 to 10 −1 s −1 . Highlights: In-situ nano-sized NiTi can serve as efficient heterogeneous nuclei of α-Al. Inoculation caused a significant refinement on α-Al and precipitation θ′ phase. The tensile strength and fracture strain were increased by 32.63% and 90.35% respectively at 533 K with 10 −1 s −1 . The enhanced tensile property was due to the finer θ′ phase which impeded dislocation motion. A stress prediction model was presented at 453 K–533 K under the strain rates of 10 −4 s −1 to 10 −1 s −1 .