Laser-Assisted Machining of a Fiber Reinforced Metal Matrix Composite

Metal matrix composites, due to their excellent properties of high specific strength, fracture resistance, and corrosion resistance, are highly sought after over their nonferrous alloys, but these materials also present difficulty in machining. Excessive tool wear and high tooling costs of diamond tools make the cost associated with machining of these composites very high. This paper is concerned with the machining of high volume fraction long-fiber metal matrix composites (MMCs), which has seldom been studied. The composite material considered for this study is an Al–2% Cu aluminum matrix composite reinforced with 62% by volume fraction alumina fibers $(Al–2%Cu/Al2O3)$⁠. Laser-assisted machining (LAM) is utilized to improve the tool life and the material removal rate while minimizing the subsurface damage. The effectiveness of the laser-assisted machining process is studied by measuring the cutting forces, specific cutting energy, surface roughness, subsurface damage, and tool wear under various material removal temperatures. A multiphase finite element model is developed in ABAQUS/STANDARD to assist in the selection of cutting parameters such as tool rake angle, cutting speed, and material removal temperature. The multiphase model is also successful in predicting the damage depth on machining. The optimum material removal temperature is established as $300°C$ at a cutting speed of 30 m/min. LAM provides a 65% reduction in the surface roughness, specific cutting energy, tool wear rate, and minimum subsurface damage over conventional machining using the same cutting conditions.