Processing and Microstructure Properties of 7055-Al Alloy Prepared by Low-Pressure Spray Forming

Abstract:

Spray forming is a new developed advanced metal-forming process, of which the property benefits from rapid solidification. The porosity produced during the atomization progress can obviously decrease the material performance. In this paper, a self-designed Laval-type atomizer is used to improve atomization efficiency. The atomization results show that the atomizer can obtain well atomization effect at a relative lower atomization pressure, and the mass median diameter d₅₀ is 63.5μm and 43.4μm when the atomization gas pressure P₀=0.4 and 0.8MPa separately. The technological parameters are optimized by overall considering the atomized droplet size, gas consumption, deposition property, and the metal yield. By the designed atomizer, the as-deposited billet with lower porosity content can be obtained with the technological parameters of the melting temperature T=800°C, atomization pressure P₀=0.6MPa, and spray distance h=500mm. Further test with the deposited billet show that the grain size of the spray formed 7055-Al alloy is mainly ranging 10~30μm, which is about one third of that of as-cast billet.

• Periodical: Applied Mechanics and Materials (Volume 574)
• Pages: 373-379
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.574.373
• Online since: July 2014
• Authors: Chao Run Si*, Xian Jie Zhang, Jun Biao Wang
• Keywords: 7055-Al Alloy, Microstructure, Over-Spray Powder, Spray Forming

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