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It. ASRACT (Contammv an ry 1 of tqmiy .iW Wonaly AVMc ta. SEE REVERSE SIDE OF PAGE. :0. OIIIRSUTvONDtAVAABUrT OF AASTPACT it. ABSTRACT SECUR11FV CLASSIFICATIN 3uVIcLAssimuktwoAI*I (3 SAME All nrP. C0 u'cultu JJ.tEAS O RSPONSW&L .h~G §emOU*J lip. WEP~N ~~Aeeci" 2U. OFFIE SY0BO6" 00 Fntnm 147J. JUN 54 Pr"O eEsv 66vt.ICURiTY CI.ASSISISATION OF full5 PAG(ABSTRACT *Tils report documents work carried out in the Materials Research Laboratory of Tie Pennsylvania State Univcrslty on the third and final year of the program on-Piezoelectric and Electrostrictive Materials for Trawzducers Applkiation." sponsoicd by the Office of Naval Research (ONRM under grand No. N00,' .-89-J-1689. This marks the termination of a very long and highly productive SCqUCnCe of contracts and grants focusing on the development of new materials for Piezoclectric and Electrostrictive transducer applications carried through under core ONJI funding. Fortunately many elements of the work will be continuing on a new University Research Initiative (URI) program under ONR sponsorship. Highlights of the past year's activities include: An increased emphasis upon the flextensional (uioonie) type actuators, modeling both the Internal stress distribution as a function of geometry, and the very Interesting resonant mode structure of the-composites; A more refined focus upon th,perforumance of piezoelectric ceramic transducers, particularly under high i'rive Is is .ieveloping with concern for the extrinsic domain and phase boundary contributions to response. Measurecent and mode'lling are being used to explore the nonlinearity ani! the frequency respons(aid to examine th," phase , 'tionling v, the rhombohedral : tetragonal morl'hotrol' hae boundary in PZT s3 i. Phenomena limiting lifetime In polarizo, 1'i, ; 'd ph, iwltchlng aci.;',ors being exlored to separate surface and volume Ollects .,iid those due to grain size and flaw population differences. New work has been initiated to examine Acoustic Emission as a technique, in combination with Barkhausen current pulse analysis. to separate and evaluate domain switching and microcracking in polarization switching systems. From work €ti this program it has now become clear that the relaxor ferroelcctrics are in fact close analugucs of the magnetic spin glasses, so that the spin glass fornalism can be used to explain the very wide range of dielectric, elastic anu-trosti ' Live properties. The remaining outstanding fundamental problem is that of the detailed Interrelationship between the known nano-heterogeneity in the structure and chemistry and the nanopolar regions which contribute the elc'trical response. Of very high practical Interest is the manner in which the relaxor can be field biased into extremely strong plczoelectric response. Work is 'lng forward to examine this response in detail and to cxplore the possibility that such "super-responses' can be induced by chemical (solid solution) means. Processing studies have focused upon new lower temperature consolidations for relaxors, and upon new compositions for...

I. WIORT SICUNIY CLAW"11101011 1b. Au&rxcTvq MA0G I&. ICUAITV CLSUICAT 'OM AJJTHOPJY 1. 0IST=MIUTIONAVAJL^SauTy OF REPORT