Investigation Of Laser Shock Processing

The objective of the program was to demonstrate that laser shock processing is a viable method of improving the fatigue and crack growth performance of mechanically fastened joints. It was shown that a decrease in crack growth rate can be achieved under specified conditions. These conditions involve compressive residual stress (induced by the process) which modify the crack shape and reduce the stress intensity factor. 2024-T3 aluminum alloy reacted better to the process than 7075-T6 aluminum. Results were better in thin (.125 inch) than thick (.250 inch) material. Initial design environmental and cost studies indicate that a laser shock processing system for use on a production line is feasible.

The objective of the program was to demonstrate that laser shock processing is a viable method of improving the fatigue and crack growth performance of mechanically fastened joints. It was shown that a decrease in crack growth rate can be achieved under specified conditions. These conditions involve compressive residual stress (induced by the process) which modify the crack shape and reduce the stress intensity factor. 2024-T3 aluminum alloy reacted better to the process than 7075-T6 aluminum. Results were better in thin (.125 inch) than thick (.250 inch) material. Initial design environmental and cost studies indicate that a laser shock processing system for use on a production line is feasible.

The objective of the program was to demonstrate that laser shock processing is a viable method of improving the fatigue and crack growth performance of mechanically fastened joints. It was shown that a decrease in crack growth rate can be achieved under specified conditions. These conditions involve compressive residual stress (induced by the process) which modify the crack shape and reduce the stress intensity factor. 2024-T3 aluminum alloy reacted better to the process than 7075-T6 aluminum. Results were better in thin (.125 inch) than thick (.250 inch) material. Initial design environmental and cost studies indicate that a laser shock processing system for use on a production line is feasible.

The objective of the program was to demonstrate that shock processing is a viable method of improving the fatigue and crack growth performance of mechanically fastened joints. It was shown that a decrease in crack growth rate can be achieved under specified conditions. These conditions involve compressive residual stress (induced by the process) which modify the crack shape and reduce and stress intensity factor. 2024-T3 aluminum alloy reacted better to the process than 7075-T6 aluminum. Results were better in thin (.125 inch) than thick (.250 inch) material. Initial design environmental and cost studies indicate that a laser shock processing system for use on a production line is feasible.

This book highlights the fundamentals and latest progresses in the research and applications of laser shock peening (LSP). As a novel technology for surface treatment, LSP greatly improves the resistance of metallic materials to fatigue and corrosion. The book presents the mechanisms, techniques, and applications of LSP in a systematic way. It discusses a series of new progresses in fatigue performance improvement of metal parts with LSP. It also introduces lasers, equipment, and techniques of newly developed industry LSP, with a detailed description of the novel LSP blisk. The book demonstrates in details numerical analysis and simulation techniques and illustrates process stability control, quality control, and analysis determination techniques. It is a valuable reference for scientists, engineers, and students in the fields of laser science, materials science, astronautics, and aeronautics who seek to understand, develop, and optimize LSP processes.

Laser shock processing (LSP) is a continuously developing effective technology used to improve surface and mechanical properties for metallic alloys. LSP is in direct competition with other established technologies, such as shot peening, both in preventive manufacturing treatments and maintenance/repair operations. The level of LSP maturity has increased in recent years and several thematic international conferences have been organized (i.e., the 7th ICLPRP held in Singapore, June 17-22, 2018) to discuss different developments of a number of key aspects. These aspects include: fundamental laser interaction phenomena; material behavior at high deformation rates/under intense shock waves; laser sources and experimental process implementation; induced microstructural/surface/stress effects; mechanical and surface properties with experimental characterization and testing; numerical process simulation; development and validation of applications; comparison of LSP to competing technologies; and novel related processes. All of these aspects have been recursively treated by well-renowned specialists, providing a firm basis for the further development of the technology in its path to industrial penetration. However, the application of LSP (and related technologies) on different types of materials with different applications (such as the always demanding aeronautical/aerospatial field or the energy generation, automotive, and biomedical fields) still requires extensive effort to elucidate and master different critical aspects. Thus, LSP deserves a great research effort as a necessary step prior to its industrial readiness level. The present Special Issue of Metals in the field of "Laser Shock Processing and Related Phenomena" aims, from its initial launching date, to collect (especially for the use of LSP application developers in different target sectors) a number of high-quality and relevant papers representing state-of-the-art technology that is useful to newcomers in realizing its wide and relevant prospects as a key manufacturing technology. Consequently, in an additional and complementary way, papers were presented at the thematic ICLPRP conferences, and a call was made to authors willing to prepare high-quality and relevant papers to the journal, with the confidence that their work would become part of a fundamental reference collection regarding the present state-of-the-art LSP technology. The Special Issue includes two reviews and nine research papers. Each contribution adds to the reference knowledge of LSP technology and covers the practical totality of open issues, which will lead to present-day research at worldwide universities, research centers, and industrial companies.

Laser shock peening (LSP) is a process for inducing compressive residual stresses using shock waves generated by laser pulses. It is a relatively new surface treatment for metallic materials that can greatly improve their resistance to crack initiation and propagation brought on by cyclic loading and fatigue. This book, the first of its kind, consolidates the scattered knowledge about LSP into one comprehensive volume. It describes the mechanisms of LSP and its substantial role in improving fatigue performance in terms of modification of microstructure, surface morphology, hardness, and strength. In particular, it describes numerical simulation techniques and procedures that can be adopted by engineers and research scientists to design, evaluate, and optimize LSP processes in practical applications.

The aim of this book is to present foundational research on the nano-crystallization, high-temperature modification, micro-structure evolution and plastic deformation induced by laser shock processing. In this regard, the focus is on heat-resistant steel, aluminum alloy, Ti alloys and Ni-based alloys, offering valuable scientific insights into the industrial applications of laser shock processing (LSP) technology. The book addresses various topics, i.e., the formation mechanism and productivity improvement of nano-crystalline diamond by laser processing, the surface integrity and fatigue lives of heat-resistant steels, Ti alloys and Ni-based alloys after LSP with different processing parameters, tensile properties and fractural morphology after LSP at different temperatures, strain-rates and grain refinement mechanisms based on the micro-structure evolution. Moreover, the effect of heating temperature and exposure time on stress thermal relaxation and the influence of compressive stress on the stress intensity factor of hole-edge cracks by high strain rate laser shock processing are also analyzed. A new type of statistical data model to describe the fatigue cracking growth with limited data is proposed based on the consideration of the effects of fracture growth on the reliability and confidence level. This book is intended for researchers, engineers and postgraduates in the fields of nanotechnology and micro-engineering who are interested in the partial or overall strengthening of materials, especially those with a focus on surface integrity and fatigue life.