This review paper discusses the recent progress in laser shock peening (LSP) of additively manufactured (AM) parts. LSP is an advanced post-processing technique that optimizes the service lives of critical components for various applications by inducing severe plastic deformation accompanied by the enhancement of surface properties in treated materials. Material improvement is enabled through the generation of high-density dislocations, grain refinement, and beneficial phase transformations. These mechanisms produce high magnitude compressive residual stresses which harden treated regions to depths exceeding 1 mm. However, a major roadblock for AM parts stems from the various fabrication processes themselves where detrimental tensile residual stresses are introduced during part manufacturing, along with near-surface voids and cracks, all of which severely limit their applications. In addition to post-fabrication heat treatment that is typically required to homogenize the microstructure and relieve the residual stresses of AM parts, post-processing surface treatments have also been developed to manipulate the residual stresses of AM materials. Tensile residual stresses generated during manufacturing affect the fatigue life of AM material negatively and could potentially surpass the material’s yield strength, resulting in acute geometric distortion. Recent studies have shown the potential of LSP to mitigate these stresses, modify the mechanical properties of the AM parts, and to close near-surface voids and cracks. Furthermore, the thermal stability of favorable microstructural modifications in laser peened AM parts, which allows for its use in high temperature environments, is not well understood and is currently limiting its effective utilization in these scenarios. The main goal of this review is to provide the detailed insight needed for widespread acceptance of this technique as a post-processing method for AM materials.

Self-healing materials with the ability to partially or completely restore their mechanical properties by healing the damage inflicted on them have great potential for applications where there is no or only limited access available to conduct a repair. Here, we demonstrate a bio-inspired new design for self-healing materials, where unit cells embedded in the structure are filled with a UV-curable resin and act as reservoirs for the self-healing agent. This design makes the repeated healing of mechanical damage possible. When a crack propagates and reaches one of these embedded reservoirs, the healing agent is released into the crack plane through the capillary action, and after polymerization through UV light exposure, bonds the crack faces. The structures here were fabricated using a stereolithography technique by a layer-by-layer deposition of the material. “Resin trapping” as a unique integration technique is developed for the first time to expand the capability of additive manufacturing technique for creating components with broader functionalities. The self-healing materials were manufactured in one step without any needs for any sequential stages, i.e. filling the reservoir with the healing agent, in contrast with the previously reported self-healing materials. Multiscale mechanical tests such as nanoindentation and three-point bending confirm the efficiency of our method.