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Inter-particle bonding in cold spray deposition of a gas-atomised and a solution heat-treated Al 6061 powder

Author:
Sabard, Alexandre, Hussain, Tanvir
Source:
Journal of materials science 2019 v.54 no.18 pp. 12061-12078
ISSN:
0022-2461
Subject:
X-ray diffraction, aluminum, aluminum alloys, coatings, cold, crystallization, feedstocks, heat treatment, homogenization, solutes, spray deposition, spraying, transmission electron microscopy
Abstract:
The heat treatment of a number of gas-atomised aluminium alloys prior to cold spraying recently showed that the resultant microstructural modification was accompanied by an improvement in deposition; however, the relationship between the microstructural homogenisation occurring after recrystallisation and the increase in deposition efficiency and particle–particle bonding had not been investigated. In this study, Al 6061 gas-atomised feedstock powder, before and after solution heat treatment, was cold sprayed and these materials were characterised using electron backscatter diffraction and transmission electron microscopy. The solution heat-treated Al 6061 powder showed large stress-free grains as opposed to the as-atomised feedstock powder which exhibited smaller grains with the presence of dislocations. The coating produced from as-received powder exhibited a homogeneous distribution of misorientation and lattice defects throughout the particles, whereas the coating produced from solution heat-treated powder showed a strain concentration in the interfacial zones. This was attributed to the partial dissolution and the clustering of solute atoms, allowing the aluminium matrix to deform around the newly formed precipitates.
Agid:
6481102