Influence of the particle morphology on the Cold Gas Spray deposition behaviour of titanium on aluminum light alloys

The present work evaluates the deposition behaviour of irregular titanium powder particles impinged by Cold Gas Spraying onto an aluminium 7075-T6 alloy substrate. The influence of their irregular shape on the bonding phenomena, in particle–substrate and particle–particle interfaces are discussed in view of Transmission Electron Microscopy examinations of a Focused Ion Beam lift-out prepared sample. Key aspects will be the jetting-out, the occurrence of oxide layers and grain size refinement. Different structural morphologies could be featured; at the particle–substrate interface, both the aluminium alloy and the titanium side exhibit recrystallization. Titanium particles in intimate contact in small agglomerates during deposition, on the other hand, show grain refinement at their interfaces whereas the original structure is maintained outside those boundaries.

► Study of the particle–substrate and particle–particle interfaces in the cold spray process.
► Use of irregular feedstock particles whereas normally FIB studies have been undergone for spherical particles.
► Deep Transmission Electron Microscopy characterization of the interfaces and within the particle.