Machinability of Al-20Mg2Si-Cu metal matrix composite modified with bismuth or barium

Aluminum metal matrix composites (MMC) have been receiving growing attention largely owing to their excellent properties, such as excellent castability and mechanical properties. These properties make them useful for high performance applications, especially for lightweight components, particularly in the manufacture of automotive parts. Al-based composite reinforced with particulate Mg2Si phase has recently been shown to possess certain advantages. However, the mechanical properties of normal cast Al-20Mg2Si-Cu metal matrix composite are unsatisfactory due to the natural coarse morphology of the primary Mg2Si phase. Therefore, the melt treatment method with refiner elements was chosen due to improve the morphology of the Mg2Si reinforcement and achieve better mechanical properties. Most of MMC parts require some machining. However, the machinability of Al-20Mg2Si-Cu metal matrix composite is not well understood yet. By adding refiner elements to the composite, the mechanical properties and machinability including particle emissions will be affected. Therefore, the main objective of this thesis is to study the machinability, and mechanical properties of Al-20Mg2Si-Cu metal matrix composite containing bismuth or barium as modifier elements. Results from the different sections of this thesis demonstrate that modifier elements such as bismuth or barium improve the mechanical properties and machinability of the composite. Using modifier elements decreases ultrafine particle emissions during the machining process, which is beneficial for operator health. In addition, the proposed mathematical models for predicting surface roughness and cutting force for this composite are in good agreement with experiment data