Composite peening - a novel processing technique for graded reinforced aluminiummatrix composites

陶瓷颗粒增强梯度复合材料在轻质、耐磨、循环加载的结构构件方面具有很高的应用潜力。尤其是热稳定性较高的表面硬化机理，可以通过使用陶瓷增强颗粒来实现。目前，成本效益高的制造工艺允许在高应力区域进行表面强化以改善机械性能，这一点还不存在。开发了一种新的基于微喷丸工艺的部件近表面区强化技术，这种技术允许定义的弥散体插入，称为复合喷丸。针对这种强化工艺，采用改进的微喷丸强化工艺，对纯铝、AlSi12 Mg和AlSiMg合金的工艺参数，如温度、喷射压力、工作距离和喷丸剂直径等进行了分析。同样，还应调整和评估进一步改善机械性能的后处理程序。制造材料状态的表征代表了该项目的中心目标，并用于与传统表面强化工艺相比较来评估复合材料喷丸工艺，也有助于实现对分级复合材料的材料理解。将研究残余应力、显微组织、界面以及硬化机制的静态和循环力学性能以及热稳定性。

Graded composites with ceramic particulate reinforcement have a high application potential for lightweight, wear-resistant and cyclically loaded structural components. Especially a high thermal stability of the surface hardening mechanisms can be achieved by use of ceramic reinforcement particles. At the moment, cost-effective manufacturing processes which allow a surface reinforcement in highly stressed areas for improving the mechanical properties are not existent. A novel reinforcing technology of near-surface areas of components based on the micro-shot peening process will be developed which allows the defined inserting of dispersoids and is called composite peening. With respect to this reinforcing process a modified micro-shot peening process shall be used to analyse the process-relevant variables, such as temperature, jet pressure, working distance and shot agent diameter, on pure Aluminium, AlSi12Mg and an AlSiMg alloy. Likewise post-treatment procedures for a further improvement of the mechanical properties shall be adapted and evaluated. The characterization of the manufactured material states represents the central aim of the project and is used for the evaluation of the composite peening process in comparison to conventional surface hardening processes and also serves to achieve a material understanding of graded composites. Residual stresses, microstructure, interface as well as the static and cyclic mechanical properties and the thermal stability of the hardening mechanisms will be investigated.