Improved inter-particle bonding of cold sprayed Ti6Al4V coatings by synchronously coupling with laser irradiation and in-situ shot peening during deposition process

As a solid-state deposition technology, cold spray (CS) offers unique advantages for depositing a wide range of materials due to its low-temperature characteristics. Ti6Al4V possesses high specific strength, excellent biocompatibility, and superior corrosion resistance, making it widely used in aerospace, petrochemical, and biomedical fields. However, its high strength leads to limited particle plastic deformation and poor mechanical properties when deposited by single CS. In this study, a hybrid process combining CS with synchronous laser irradiation and in-situ shot peening (SP) is proposed for fabricating Ti6Al4V deposits. The microstructure, nano-indention mechanical properties, and inter-particle bonding behaviors of the coatings are systematically analyzed. Dense CS-Ti6Al4V coatings are successfully produced using a relatively low volume fraction of SP particles under laser irradiation. At a laser power of 800 W and with the addition of 30 vol% SP particles, the porosity of the as-deposited coating is reduced to 0.71%, comparable to that achieved with 70 vol% SP particle in the single in-situ SP process. Furthermore, the inter-particle bonding exhibits metallurgical characteristics accompanied by severe particle plastic deformation owing to the synergistic effects of laser irradiation and in-situ SP. This study provides a novel approach for producing dense Ti6Al4V deposits using a low volume fraction of SP particles under laser irradiation in surface modification and additive manufacturing with CS.