There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Cold spray is a solid-state coating deposition technology which has recently been applied as an additive manufacturing process to fabricate individual components and to repair damaged components. In comparison with fusion-based high-temperature additive manufacturing processes, cold spray additive manufacturing (CSAM) has been shown to retain the original properties of the feedstock, to produce oxide-free deposits, and to not adversely influence underlying substrate materials during manufacture. Therefore, CSAM is attracting considerable attention from both scientific and industrial communities. Although CSAM is an emerging additive manufacturing technology, a body of work has been carried out by various research groups and the technology has been applied across a range of manufacturing areas. The purpose of this paper is to systematically summarize and review the CSAM-related work to date.

Cold spray additive manufacturing and repair: Fundamentals and applications

Research and development status of laser cladding on magnesium alloys: A review

Additive manufacturing (AM), often termed 3D printing, has recently emerged as a mainstream means of producing metallic components from a variety of metallic alloys. The numerous benefits of AM inc...

Corrosion of Additively Manufactured Alloys: A Review

Critical Influences of Particle Size and Adhesion on the Powder Layer Uniformity in Metal Additive Manufacturing

In current study the kinetics of thick single track formation during cold spraying of 316L stainless steel powder is considered. It is shown that at low nozzle traverse speed the tracks have triangular-like profiles and powder deposition efficiency significantly depends on the triangle height. In particular, increasing of track height leads to significant decreasing of deposition efficiency (more than 35%) due to diminishing of effective impact angle between particles and surface. Numerical simulation results show that parameters of near-substrate compressed gas layer change during coating growth. Compressed gas layer becomes thicker at the jet periphery that decreases particle impact velocity that also influences the particle deposition efficiency in this zone.

Influence of a shape of single track on deposition efficiency of 316L stainless steel powder in cold spray

Distortions and Residual Stresses at Layer-by-Layer Additive Manufacturing by Fusion

Selective laser melting is the method for 3D printing from metals. A solid part is built from powder layer-by-layer. A continuum-wave laser beam scans every powder layer to fuse powder. The process is studied with a high-speed CCD camera at the frame rate of 104 fps and the resolution up to 5 µm per pixel. Heat transfer and evaporation in the laser-interaction zone are numerically modeled. Droplets are ejected from the melt pool in the direction around the normal to the melt surface and the powder particles move in the horizontal plane toward the melt pool. A vapor jet is observed in the direction of the normal to the melt surface. The velocities of the droplets, the powder particles, and the jet flow and the mass loss due to evaporation are measured. The gas flow around the vapor jet is calculated by Landau’s model of submerged jet. The measured velocities of vapor, droplets, and powder particles correlate with the calculated flow field. The obtained results show the importance of evaporation and the flow of the vapor and the ambient gas. These gas-dynamic phenomena can explain the formation of the denudated zones and the instability at high-energy input.

D. V. Kotoban

Papers

Influence of a shape of single track on deposition efficiency of 316L stainless steel powder in cold spray

Distortions and Residual Stresses at Layer-by-Layer Additive Manufacturing by Fusion

Evaporation-induced gas-phase flows at selective laser melting

Comparative Study of Selective Laser Melting and Direct Laser Metal Deposition of Ni3Al Intermetallic Alloy

Study of 3D laser cladding for Ni85Al15 superalloy