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Mechanical and Thermal Characterization of Ultrasonic Additive Manufacturing

Foster, Daniel

Abstract Details

2014, Doctor of Philosophy, Ohio State University, Welding Engineering.
Additive manufacturing is an emerging production technology used to create net shaped 3-D objects from a digital model. Ultrasonic Additive Manufacturing (UAM) is a relatively new type of additive manufacturing that uses ultrasonic energy to sequentially bond layers of metal foils at temperatures much lower than the melting temperature of the material. Constructing metal structures without melting allows UAM to have distinct advantages over beam based additive manufacturing and other traditional manufacturing processes. This is because solidification defects can be avoided, structures can be composed of dissimilar material and secondary materials (both metallic and non-metallic) can be successfully embedded into the metal matrix. These advantages allow UAM to have tremendous potential to create metal matrix composite structures that cannot be built using any other manufacturing technique. Although UAM has tremendous engineering potential, the effect of interfacial bonding defects on the mechanical and thermal properties have not be characterized. Incomplete interfacial bonding at the laminar surfaces due to insufficient welding energy can result in interfacial voids. Voids create discontinuities in the structure which change the mechanical and thermal properties of the component, resulting in a structure that has different properties than the monolithic material used to create it. In-situ thermal experiments and thermal modeling demonstrates that voids at partially bonded interfaces significantly affected heat generation and thermal conductivity in UAM parts during consolidation as well as in the final components. Using ultrasonic testing, elastic properties of UAM structures were found to be significantly reduced due to the presence of voids, with the reduction being the most severe in the transverse (foil staking) direction. Elastic constants in all three material directions decreased linearly with a reduction in the interfacial bonded area. The linear trend permits the ability to predict bonded interfacial area in the manufacturing environment without the need for destructive mechanical or metallurgical tests. The feasibility of two process monitoring techniques for UAM were also evaluated. A method to test resonance frequency using a Photonic Doppler Velocimeter to detect vibrational motion was developed and tested. Preliminary testing revealed that resonance testing could be used to determine average interfacial bonded area in a UAM sample. In-situ vibration velocity of the sonotrode, welding foil and substrate were measured using the Photonic Doppler Velocimeter system. Analysis of the velocity data revealed that by analyzing absolute velocity, relative velocity and phase angles of the three structures a bonding vs. non-bonding conditions could be determined in-situ using the Photonic Doppler Velocimeter system.
Wei Zhang, PhD (Advisor)
Sudarsanam Suresh Babu, PhD (Committee Member)
Glenn Daehn, PhD (Committee Member)
Stanislav Rokhlin, PhD (Committee Member)
234 p.

Recommended Citations

Citations

  • Foster, D. (2014). Mechanical and Thermal Characterization of Ultrasonic Additive Manufacturing [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1398997070

    APA Style (7th edition)

  • Foster, Daniel. Mechanical and Thermal Characterization of Ultrasonic Additive Manufacturing. 2014. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1398997070.

    MLA Style (8th edition)

  • Foster, Daniel. "Mechanical and Thermal Characterization of Ultrasonic Additive Manufacturing." Doctoral dissertation, Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1398997070

    Chicago Manual of Style (17th edition)