Composite Peening - A Novel Processing Technology for Graded Reinforced Aluminium Matrix Composites

Abstract

Recently, the attention paid to Metal Matrix Composites (MMCs) has increased markedly. In particular, particle-reinforced MMCs are outstanding due to superior specific properties and their wear resistance. In order to further improve material utilization, recent investigations with local reinforcements in highly stressed component sections, the so-called Functionally Graded Metal Matrix Composites (FGMMC), are concerned. The production of such FGMMC was realized with composite peening - a modified process on the basis of micro shot peening. Due to this solid-phase process, ceramic particles can be introduced into regions close to the boundary layer. As preliminary studies on tin show, ceramic particles can be introduced close to the specimen surface even at room temperature. By varying process parameters, in particular by increasing the temperature, the penetration depth of the particles can be significantly increased. In case of aluminium as base material, an input of particles into the surface could be observed at a process temperature of 150 °C. The combination of aluminium with reinforced ceramic particles makes this process interesting for lightweight, wear-resistant and cyclically highly stressed structural components. Using composite peening to produce FGMMCs is a novel, economic approach.

Influence of the Process Parameters on the Penetration Depth of the Reinforcing Phase during Composite Peening for the Production of Functionally Graded Metal Matrix Composites

“…Furthermore, it should be mentioned that the blasting particles are significantly smaller after the peening process. This has also been determined in preliminary investigations [9]. The reasons for this have not yet been finally clarified.…”

“…It is known that micro peening can introduce particles into the surface [8]. At high homologous temperatures, an increased penetration depth could be demonstrated by the authors on the model material tin [9]. These results shall be transferred to aluminium as matrix material in the following investigations.…”

“…Experimental setup: To introduce ceramic particles into the aluminium matrix, a high homologous temperature is needed [9]. For this reason, a heating device was added to the micro shot peening system.…”

Characterization of the Microstructure after Composite Peening of Aluminum

“…Composite peening describes a process based on micropeening developed by the authors and first published in 2017. [16] A detailed description and scheme of the setup of the composite peening system is described elsewhere. [2] By adding a heating device, it was possible to introduce the blasting particles in the heated substrate material (Al 1050).…”