Microstructural Characterization and Mechanical Property of Al-Li Plate Produced by Centrifugal Casting Method

• Published in: Metals (Basel ) 2021-06, Vol.11 (6), p.966
• Main Authors: Tian, Qingle, Deng, Kai, Xu, Zhishuai, Han, Ke, Zheng, Hongxing
• Format: Article
• Language: English
• Subjects: Al-Li alloy; Alloys; Aluminum; Anisotropy; Annealing; Centrifugal casting; Cold; Cold rolling; Cooling; Copper; Deformation; Electron probe microanalysis; Elongation; Grain boundaries; Hot rolling; Intergranular fracture; Mechanical properties; mechanical property; microstructure; Morphology; Nanoparticles; Powder metallurgy; Precipitates; Solid solutions; Strengthening; Ultimate tensile strength
• ISSN: 2075-4701; 2075-4701
• DOI: 10.3390/met11060966

Using a centrifugal casting method, along with deformation and aging, we produced a high-strength, low-anisotropy Al-Li plate. The electron probe microanalysis, transmission electron microscope, differential scanning calorimetry, and X-ray diffraction were used to clarify the evolution of strengthening phases. Experimental results showed that centrifugal-cast Al-Li plate consisted of intragrain δ′—(Al,Cu)3Li precipitate and interdendritic θ′—Al2Cu particles. After cold-rolling to a reduction ratio of 60% and annealing at 800 K for 90 min, both primary θ′ and δ′ were dissolved in solid solution. Aging at 438 K for 60 h led to the formation of two kinds of precipitates (needle-like T1—Al2CuLi and spherical δ′ in two sizes), which acted as the main strengthening phases. The average values of ultimate tensile strength and yield strength for the anneal-aged plate reached 496 MPa and 408 MPa, with a total elongation of 3.9%. The anneal-aged plate showed mechanical anisotropy of less than 5%. The tensile fracture morphology indicated a typical intergranular fracture mode.