Effects of a hybrid post-treatment on microstructure and mechanical properties of cold sprayed AA7050 deposits

• Published in: Journal of alloys and compounds 2024-05, Vol.985, p.174031, Article 174031
• Main Authors: Liu, Chengxin, Chu, Xingrong, Wang, Naijiang, Gao, Jun, Chen, Liang
• Format: Article
• Language: English
• Subjects: Additive manufacturing; Aluminum alloy; Cold spray; Heat treatments; Mechanical properties; Microstructure
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2024.174031

Cold spray additive manufacturing (CSAM) technology is a promising and efficient method for preparing high-strength aluminum alloy components. In this work, AA7050 deposits were prepared by high-pressure cold spraying, and a hybrid post-treatment (i.e., annealing + hot compression + solid solution and aging) was proposed to improve the mechanical properties of the deposits. The results of the study indicated that the annealing alone was insufficient to eliminate all defects within the AA7050 deposits. After annealing, the porosity of the material decreased from 2.34% to 1.62%. The subsequent hot compression and aging treatment promoted the precipitation of strengthening phases and homogenized the microstructure, reducing the porosity of the AA7050 deposits to 0.18%. As a result, the mechanical properties of the materials further improved. The ultimate tensile strength of the CSAMed AA7050 after aging treatment reached 557.7 MPa, which was 337.4% and 149.3% higher than that of the as-sprayed and annealed materials, respectively. Furthermore, fracture surfaces analysis indicated that the fracture mechanism of the specimens changed from brittle to ductile mode after the hybrid post-treatment. •Hot compression was introduced before aging treatment of cold sprayed AA7050 deposit.•Microstructural evolution during the hybrid post-treatment was analyzed.•Tensile properties were significantly enhanced with an increase of 337.4% for UTS.•Maximum elongation presented an increase of 1173.2% after hybrid post-treatment.