Pulsed Electron Bean (PEB) Fabrication of Smart Materials

The objective of this proposal is to demonstrate the feasibility of fabricating a smart material containing layers of piezoelectric transducers bonded to shape memory alloy layers. The critical problem in fabricating these smart materials is to produce a ceramic-metal bond that can endure the high stress-strain state cycles to which it will be subjected in use. This bonding cannot be accomplished using conventional techniques that heat the entire assembly. In this project a pulsed electron beam (PEB) bonding system will be fabricated and tested. PEB irradiation has the capability of depositing the electron energy preferentially near the bond interface, producing a temperature profile than can fuse the dissimilar materials together with the potential to leave the bulk properties of the piezoelectric and shape memory alloy intact. In this Phase I project lead lanthanum zirconium titanate (PLZT) piezoelectrics and Ni-Ti shape memory alloys will be subjected to PEB irradiation and their properties evaluated before and after irradiation. The PEB parameters (e.g., electron energy, beam pulse length and repetition rate) will be set based upon Monte Carlo computer simulations that predict temperature profiles leading to bonding. Piezoelectric elements will be bonded to shape memory alloy foils in Phase II using the beam parameters determined in this Phase I project and the properties of the bonded materials evaluated. Anticipated Benefits: Vibration cancellation systems based upon the proposed smart materials could be applied to machine tools or the tool-machine interface to enable precision machining (e.g., 0.1 mil tolerance) without the use of expensive or large cutting machines or tool holders. The impact on the aerospace, automotive and other industries of low cost precision machining could be in the billions of dollars per year in cost reduction and improved productivity.