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The purpose of composite peening is to introduce ceramic dispersoids by a micropeening process into near-surface regions of aluminum alloys to generate a graded metal matrix composite. It was observed that particle embedding by micropeening is possible and doing so an increase in hardness was achieved. The authors have demonstrated that heating the peened sample during the micropeening process increases the penetration depth of the ceramic blasting particles. The embedded particles may act as a reinforcement of the surface regions similar to coating processes such as cold gas spraying. This may lead to an enhancement in mechanical or tribological properties. Previous investigations on commercially available, pure Al (Al 1050 alloy) showed that a hill–valley profile is formed on the surface as a result of composite peening. Embedded ceramic particles are mainly found in the valleys. At temperatures close to the solidus temperature Ts (homologous temperature T/Ts1⁄4 0.95), it is possible to introduce alumina particles to a depth of up to 30 μm.The ceramic particles could be found in isolated regions and were significantly smaller compared to the original size. Research in the field of solid particle erosion is closely related to research on shot peening and composite peening. Although these investigations are primarily focused on describing erosion phenomena and avoiding erosion, the devices used to investigate erosion behavior are similar to those used for shot peening. For example, air-blast erosion testers, free-fall testers, and wheel blast methods are used, which are also used in applications of shot peening. In addition to the similarities in the experimental setups, many investigations in the field of solid particle erosion discussed in the following also show that fragments of the erosion particles remain stuck and/or are embedded. Different substrates such as Al, Cu, and polymers were subjected to ceramic erosion particles. Brown et al. observed a distinct hill–valley profile of the eroded surface of the Al 1100 base material after the erosion process. A minimum particle size of 20 μm was assumed to be required to form such a profile. While smaller (70 μm) silica spheres showed no embedding, larger (210 μm) erodent fragments of the abrasive silica and quartz were found embedded in near-surface regions. In the case of the angular quartz particles, pockets of ceramic fragments were found which were separated by regions without embedded particles. The investigations published in Doyle and Levy are focused on the erosion behavior of Al 1100 at elevated temperatures up to a homologous temperature of 0.8. At an incident angle of 90 , the SiC particles (250–300 μm) form patterns of hills and valleys and embedded particles are found in the valleys. While a comparably high velocity of the blast particles can be achieved with the jet and impeller methods, the particle velocity in the free-fall experiments of Zu et al. was below 10m s . Nevertheless, fragments of sand particles were found in M. Seitz, Dr. A. Kauffmann Institute for Applied Materials (IAM-WK) Karlsruhe Institute of Technology (KIT) Engelbert-Arnold-Straße 4, 76131 Karlsruhe, Germany E-mail: [email protected] Dr. M. Dürrschnabel Institute for Applied Materials (IAM-AWP) Karlsruhe Institute of Technology (KIT) Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany C. Kurpiers, Dr. C. Greiner Institute for Applied Materials (IAM-CMS) Karlsruhe Institute of Technology (KIT) Straße am Forum 7, 76131 Karlsruhe, Germany Prof. K. A. Weidenmann Institute of Materials Resource Management Augsburg University Universitätsstraße 1, 86159 Augsburg, Germany