Lawrence Livermore National Laboratory (LLNL), operated by the Lawrence Livermore National Security (LLNS), LLC under contract with the U.S. Department of Energy (DOE), is offering the opportunity to license and commercialize its High Velocity Laser Accelerated Deposition (HVLAD) technology for Controlled Laser-Driven Explosive Bonding- an extension of Laser Peening Technology for the Uniform and Patterned Deposition of Functional Films and Coatings with Exceptionally Strong Adhesion. This technology was selected by R&D Magazine as one of the 2012 R&D100 Award Winners.
This state-of-the-art additive manufacturing process is enabled and facilitated by LLNL's unparalled international leadership in high-performance solid-state laser technology. This process uses the world's most powerful and highest repetition rate production lasers for localized explosive bonding, thus producing a very broad range of advanced high-temperature and corrosion-resistant coatings with extreme interfacial bond strength. These interfacial bonds approach the ultimate tensile strength of the substrate.
The deposition of protective metallic films and coatings on various metallic alloy, ceramic or composite substrates is important for many industrial applications. LLNL has now demonstrated that exceptionally corrosion and wear resistant coatings can be deposited with exceptional interfacial bond strengths, approaching the ultimate strengths of the underlying substrate materials. This process is particularly interesting in that it can be conducted in manufacturing plants, aircraft hangers, and ship yards under ambient conditions (in air at room temperature). These unique coatings are made possible through controlled laser-driven explosive bonding, which uses a laser pulse to accelerate coating material towards the substrate.
This technology comprises a method of depositing coatings of dissimilar materials on a substrate. A laser pulse hits the film of deposited material covered by a thin water layer. The laser deposition on the water-material interface generates huge pressure accelerating film to the velocities a few hundred meters per second. The film hits the substrate at an oblique angle. The high velocity of impact induces the plastic flow of materials on film-substrate interface and shear flow due to the oblique incidence results in material mixing and strong coating adhesion.
The five discrete steps involved in the deposition are as follows: (Step 1) the high-performance corrosion resistant film material is advanced with a spool assembly, and bathed with water that serves as a tamper during laser pulse; (Step 2) a special laser pulse with rectangular beam cross-section is imaged onto the advancing high-performance film material bathed with a thin layer of water; (Step 3) the laser pulse generates a high temperature plasma and very large pressure shearing out a section of film accelerating it to hypersonic velocities; (Step 4) patches of ultra-hard and corrosion-resistant film are accelerated and bonded to the substrate in a controlled step-by-step process creating coating; (Step 5) the film patch hits the substrate at an oblique angle, where the high impact velocity induces plastic shear flow at the interface creating a high-strength explosive bond.
This method is compatible with LLNL's already commercialized laser peening technology, which can also be leveraged for production level implementation of this new coating process.
The advantages of LLNL's controlled laser-driven bonding include:
LLNL has a patent application filed covering this technology.