Engineering

Particle velocity

Materials science

Coating

Particle size

Chemical engineering

Jet (fluid)

Geology

Oceanography

Physical chemistry

Thermodynamics

Physics

Work (physics)

Particle (ecology)

Composite material

Chemistry

Critical ionization velocity

Mechanics

Gas dynamic cold spray

Acta Materialia

In cold spray processing of metals, the critical velocity for particle bonding is dependent on both intrinsic material properties, such as density and (spall) strength, and extrinsic process parameters, such as the powder particle size. In this work, we specifically isolate and investigate particle size effects on the critical velocity for bonding through laser-induced single particle impact experiments and finite element simulations. We also present a predictive framework to correlate particle size and critical velocity. We show that an increase in particle size leads to an increase in the temperature of the jet formed at the interface of the particle and the substrate. This increased temperature locally decreases the spall strength of the material which, in turn, decreases the critical velocity for larger particles.

Particle size effects in metallic microparticle impact-bonding