Browsing by Subject "Ultrasonic consolidation"
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Item Multi-Material Ultrasonic Consolidation(2006-09-14) Janaki Ram, G. D.; Robinson, C.; Stucker, B. E.Ultrasonic consolidation (UC) is a recently developed direct metal solid freeform fabrication process. While the process has been well-demonstrated for part fabrication in Al alloy 3003 H18, including with intricate cooling channels, some of the potential strengths of the process have not been fully exploited. One of them is its flexibility with build materials and the other is its suitability for fabrication of multi-material and functionally graded material parts with enhanced functional or mechanical properties. Capitalizing on these capabilities is critical for broadening the application range and commercial utilization of the process. In the current work, UC was used to investigate ultrasonic bonding of a broad range of engineering materials, which included stainless steels, Ni-base alloys, brass, Al alloys, and Al alloy composites. UC multimaterial part fabrication was examined using Al alloy 3003 as the bulk part material and the above mentioned materials as performance enhancement materials. Studies were focused on microstructural aspects to evaluate interface characteristics between dissimilar material layers. The results showed that most of these materials can be successfully bonded to Al alloy 3003 and vice versa using the ultrasonic consolidation process. Bond formation and interface characteristics between various material combinations are discussed based on oxide layer characteristics, material properties, and others.Item A Study of Static and Dynamic Mechanical Behavior of the Substrate in Ultrasonic Consolidation(2006-09-14) Zhang, Chunbo; Li, LeijunA new 2-D FEM model is developed for a fundamental study of the time dependent mechanical behavior of the substrate in ultrasonic consolidation. The simulation shows that for a given vibration condition, the amplitude of contact friction stress and displacement stabilize to a saturated state after certain number of ultrasonic cycles. With the increased substrate height, the amplitude of contact frictional stress decreases, while that of contact interface displacement increases. The energy density and transfer coefficient at the contact interface with different substrate heights can be used as parameters to predict the potential for ultrasonic bonding. The reason for the decrease in the frictional stress and displacement at the contact interface for certain substrate height seems to be caused by the complicated wave interference occurring in the substrate. A specific substrate geometry generates a minimum strain state at the interface as a result of wave superposition. Such minimum strain state is believed to have produced the “lack of bonding” defect.