The Need

To date, a key method of lightweighting automobiles has been “down-gauging” sheet metal components or changing to a “lightweight” material such as aluminum from steel. Reducing sheet metal gage has a limitation in formed metal components based upon strength, stiffness, energy absorption or fatigue properties. Further, lightweight materials may be less dense than steel but they often have lower strength and are proportionally less stiff. In a similar manner, extruded components must have a uniform wall thickness, and therefore a uniform strength and stiffness, along the extrusion direction based on the requirements of the most highly loaded region of the part. An optimal solution for parts would include a multimaterial component with spatially varying strength and stiffness to achieve reduced mass and required strength and stiffness. Multimaterial solutions have barriers in the current automotive manufacturing process including forming, fixity (location stability during the manufacturing process), joining, and thermal expansion. Further, spatial property variation is only coarsely possible with current manufacturing technology.

The Technology

In this invention, led by Marcelo Dapino and Ohio State University researchers, reinforcement is added to a forming blank or stock extrusion section prior to the forming process. The reinforcement may be added via Ultrasonic Additive Manufacturing (UAM) which enables special capabilities with regard to fiber embedment and dissimilar material joining. Reinforcement is placed on the blank in such a way that post-forming, reinforcement is located in key areas of the formed component for enhanced properties such as strength, stiffness, or energy absorption capabilities. The reinforcement itself may be a homogenous, such as a stronger grade of material, may be a discretely reinforced metal matrix composite (DRx), or may include secondary reinforcement materials, such as high strength steel wires, titanium fibers, carbon fibers, etc. In the latter case, the secondary reinforcing materials, whether they are fibers, ribbons, or other geometries, may be coated in a lubricant or resin that either cures over time or in response to a thermal treatment. Areas where reinforcement is applied may be preprocess via subtractive processes or an initial local forming process to create channels or pockets to more easily accommodate the secondary reinforcing materials. The invention is in some cases dependent upon the subsequent forming, joining, and/or heat treatment processes that take place in the typical manufacturing process to develop the interface and/or bond between the reinforcement and base materials.

Commercial Applications

• Automotive Manufacturing
• Ultrasonic Additive Manufacturing (UAM)

Benefits/Advantages

• Lighweight construction
• Higher performance (e.g. strength, stiffness, energy absorption, and fatigue life) than homogenous sheet material
• Tailored, spatially variable properties
• More robust integration of reinforcement
  • Reinforcements can be incorporated earlier in the manufacturing process due to a wider acceptable temperature range
• Reduced part count
• Reduced manufacturing costs by eliminating ultra high strength blanks, hot formed blanks, and tailor welded/tailor rolled blanks