High velocity impact induced microstructure evolution during deposition of cold spray coatings: A review

• Published in: Surface & coatings technology Vol. 254; pp. 11 - 20
• Main Authors: Luo, Xiao-Tao, Li, Cheng-Xin, Shang, Fu-Lin, Yang, Guan-Jun, Wang, Yu-Yue, Li, Chang-Jiu
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.09.2014; Elsevier
• Subjects: Applied sciences; Coatings; Cold spraying; Cross-disciplinary physics: materials science; rheology; Deformation; Densification; Deposition; Dislocations; Exact sciences and technology; High strain rate plastic deformation; Materials science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Microstructure; Microstructure evolution; Physics; Production techniques; Residual stress; Spray coating; Sprayers; Sprays; Surface treatment; Surface treatments; Cold spraying; Densification; High strain rate plastic deformation; Residual stress; Microstructure evolution; Spray coatings; Hot spraying; Mechanical properties; Surface treatments; Residual stresses; Plastic deformation; Coatings; High speed; Microstructure; Strain rate
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2014.06.006

Cold spray is a fast growing coating process involving in high strain rate deformation of spray particles. Early investigations stressed the retaining of feedstock microstructures into deposits. However, in recent years, metastable microstructures including high density of dislocations, nanosized grains and localized amorphous phase have been frequently observed through detailed microstructure characterization and it was found that those metastable microstructures remarkably affect the coating properties. In this review article, the evolution mechanisms of metastable microstructure in a cold spray coating during deposition of spray particles were examined in terms of in-situ densification, residual stress, dislocation multiplication, grain refining, phase transformation and amorphization through typical materials. Feedstock microstructure design, in-process control and material selection are essential approaches to acquire the coatings with desired microstructure. •High speed impact induced microstructure evolution during deposition was reviewed.•Residual stress in cold sprayed coatings can be either tensile or compressive.•Tamping effect can be used to prepare super-hard coating by porous powder design.•Metastable microstructures benefit improving coating properties.