Preventing Cracks in 3D Printing with New Techniques

Ultrasonic additive manufacturing system for joining and repairing metal structures using a contoured sonotrode that rotates and translates to reduce defects when welding metal foils. The contoured welding surface profile prevents cracks and weak spots in the welds when joining or repairing metal parts. The contour eliminates interfaces normal to the weld direction, reducing defects compared to flat weld surfaces. The system involves positioning metal structures adjacent to each other, creating a contoured channel along the interface, and filling it with metal foils using the rotating and translating sonotrode for welding. This reduces cracking and weak points compared to conventional ultrasonic welding.

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3D printing metal objects without warping or cracking by using a tacky polymer substrate. The process involves spreading a layer of metal particles over a polymer substrate with low thermal conductivity and melting the unmasked metal with pulsed light to form each layer of the object. The polymer substrate reduces lateral heat transfer during melting, preventing warping and cracking.

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This method reduces microcracking in additively manufacturing superalloys like nickel-based alloys by using a mixture of high-melt and low-melt superalloy powders. The low-melt powder has a lower solidus temperature than the high-melt powder. When combined in the right ratios, this powder mixture reduces cracking during additive manufacturing compared to using only the high-melt powder.

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A nickel-based superalloy composition for use in selective laser melting (SLM) to enable crack-free processing of Ni-based superalloys with high gamma prime content. The alloy composition contains a minimum of 1.2 wt % Hafnium and has a Hf/C atomic ratio >1.55.

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Body-mounted components like orthoses have improved flexibility and resistance to breakage when bent. The components are made by 3D printing using a resin material with high elongation at break when stretched. This elongation property allows the 3D-printed parts to bend and stretch without breaking.

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Steel material for additive manufacturing of tools with excellent mechanical properties and resistance to cracking without preheating. The steel composition contains 0.3-0.6% carbon, 3.5-12% chromium, 0.5-4% molybdenum, and 0-3% nickel, with the sum of chromium and molybdenum being 4-16%.

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Ultrasonic additive manufacturing system using a contoured sonotrode to minimize cracking and weak areas when joining and repairing metal structures. The system has a rotating sonotrode with a welding surface that is contoured, such as V-shaped or curved. The contoured profile allows the sonotrode to eliminate interfaces normal to the weld direction, reducing defects. When joining or repairing metal structures, channels with matching contoured profiles are created. Metal foils are then welded into the channels using the sonotrode. This reduces cracking and weak areas compared to conventional flat sonotrodes.

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Laser additive manufacturing methods for high-strength aluminum alloys that suppress residual stress cracking. The methods involve modifying laser scanning parameters like speed, power, and scan path to reduce solidification strain during additive manufacturing.

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Additive manufacturing of gas turbine components with internal tunable auxetic structures to mitigate cracking. The internal structures are made from a repeating pattern of interconnected 3D auxetic unit cells. The unit cell is made from intersecting dimpled sheets that exhibit negative Poisson's ratio behavior. This enables the internal structure to contract instead of expand when heated, reducing stresses that can cause cracking. The auxetic structure can be additively manufactured with the component to avoid stress concentrations from separate supports.

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