Laser processing of discontinuously reinforced aluminum composites

Aluminum matrix composites offer many improvements in structural properties over conventional aluminum alloys for design-critical components. Primary fabrication technology for the composites has been improving, leading to greater utility and decreased cost. Unfortunately, secondary processing techniques such as cutting, shaping, and joining have been lacking. Conventional machining techniques are hampered by rapid tool wear due to the wear resistance of the composites. Fusion joining techniques are often hampered by interactions between the matrix and the reinforcement material. Laser processing can offer many advantages over conventional techniques. During this investigation, aluminum alloys reinforced with alumina and silicon carbide were studied for their ability to be laser processed using a 1.5 kW CO₂ laser. Laser cutting parameters were developed for cutting of both types of materials. Laser beam welding experimentation was primarily concerned with suppression of the formation of aluminum carbide in silicon carbide reinforced materials. Filler alloy additions of titanium were supplied to the weld to supersede the formation of aluminum carbide.