Graphene reinforced metal composite has been a promising materials with superior mechanical properties. Currently the mechanical properties of the additively manufactured metals are limited by the undesired microstructures and residual stress due to the laser melting process. Strengthening in graphene/metal composite is limited to the intrinsic strength of graphene and its ability to block dislocation from propagation, which make it very difficult to introduce dislocation hardening and twin boundary strengthening. Here, a hybrid manufacturing process combining layer by layer laser deposition of graphene/metal nanocomposites and laser shock peening has been investigated through modeling and experiments. Strengthening of graphene/metal composites is introduced by the strong interactions between shock wave and selective laser sintered graphene/metal composite. Instead of constraining the dislocation motion, graphene acts as a shock-loading transferor to allow shock wave to pass through and bounce back between them, resulting in high density dislocations and nanotwinning structures around graphene/metal interface. Molecular dynamics (MD) simulation shows that the shock interaction with the graphene/metal interface generates dislocations pile-up in front of graphene and large stress intensity around the interface. Wave-like nanowrinkles in graphene are generated after laser shock loading because of interference wave propagation. Mechanical testing results showed that the laser shock treated graphene/metal composites enable ultra-stability of strength and compressive residual stress, and excellent fatigue performance. MD simulation revealed that shock wave strengthened graphene/metal interface significantly reduces the crack propagation rate and provides strong resistance to fatigue of metal/graphene composites.

石墨烯增强金属复合材料一直是具有优异机械性能的有前途的材料。目前，由于激光熔化过程，不希望有的微观结构和残余应力限制了增材制造金属的机械性能。石墨烯/金属复合材料的增强仅限于石墨烯的固有强度及其阻止位错扩散的能力，这使得引入位错硬化和双边界强化非常困难。在这里，已经通过建模和实验研究了混合制造工艺，该制造工艺结合了石墨烯/金属纳米复合材料的逐层激光沉积和激光冲击喷丸。冲击波与选择性激光烧结石墨烯/金属复合材料之间的强相互作用引入了石墨烯/金属复合材料的增强作用。石墨烯没有限制位错运动，而是充当冲击加载转移器，使冲击波能够通过并在它们之间反弹，从而导致高密度位错和石墨烯/金属界面周围的纳米孪晶结构。分子动力学（MD）模拟表明，与石墨烯/金属界面的冲击相互作用在石墨烯前面产生位错堆积，并在界面周围产生较大的应力强度。激光冲击加载后，由于干扰波的传播，石墨烯中的波浪状纳米皱纹产生了。机械测试结果表明，经激光冲击处理的石墨烯/金属复合材料可实现强度和压缩残余应力的超稳定性，并具有出色的疲劳性能。MD模拟显示，冲击波增强的石墨烯/金属界面显着降低了裂纹扩展速率，并具有较强的抗金属/石墨烯复合材料疲劳性。