In recent years, cold spray technology has attracted more and more attentions. After more than 30 years of rapid development, research focus of cold spray technology is gradually shifting from fundamental and theoretical studies to application developments, some of which have been industrialized and mass-produced. In this paper, the characteristics of cold spray technology, cold spray materials perspectives and cold spray system developments were briefly introduced. Besides, the recent developments of cold spray applications in different fields including aerospace, biomedical, energy, electronics, semiconductor fields were discussed. Although cold spray technology is in the early stages of implementation, it has demonstrated a great potential to reduce costs and improve performance. World-wide awareness of ongoing and planned cold spray programs is critical to expand its applications and benefits.

In this study, CoCrMo alloy coatings were fabricated by high pressure cold spray deposition. Laser shock peening with and without an ablative layer was applied to the coatings. The microstructure characteristics and mechanical properties of the both as-sprayed and laser shock peened CoCrMo coatings were systematically investigated. Laser shock peening without a protective overlay resulted in both mechanical and thermal loading of the coatings, leading to melting and solidification of the outermost surfaces of the coatings along with deformation. For comparison, laser shock peening with a polyvinyl tape as sacrificial layer was also applied to the as-sprayed CoCrMo coatings. It was found that this sacrificial layer could protect the samples from thermal effects and introduce a deep compressive residual stress in the coatings, which resulted in cracks in the coating. Those cracks in the coatings appeared to be continuous and parallel to the coating/substrate interface due to the strong shock wave imposed during the laser peening process.

In this study, Inconel 718 coatings were deposited by the high-pressure cold spray technique, and post-process solution and double aging treatments were conducted. The microstructures of the as-deposited and heat-treated IN718 were analyzed, and their mechanical properties were tested. It was found that the micro-dendritic structures in the original powder were severely elongated in the as-deposited IN718 coating due to plastic deformation during the cold spray process. After solution heat treatment, Nb, Mo, and Ti-rich segregations could be dissolved, transforming to MC carbide and a needle-like δ phase. It was found that the needle-like δ phase at the grain boundary had a pinning effect to slow down the grain growth. In addition, strengthening phases could be formed by aging treatments. The mechanical properties of the cold sprayed Inconel 718 could be improved by proper solution and aging heat treatments.