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FW: SEMINAR NOTICE: Christopher M. Fancher, PhD Final Exam, Thur. 4/4/13, HAMP 1113
by Stacey, Lisa A 28 Mar '13

28 Mar '13

Please note seminar location: MATERIALS SCIENCE AND ENGINEERING SEMINAR Texture and Anisotropy in the Bismuth Sodium Titanate System By: Christopher M. Fancher Ph.D. Final Examination Co-Advisors: Prof. K. J. Bowman and Prof. J. E. Blendell ABSTRACT Bi0.5Na0.5TiO3 has received interest as a potential replacement for lead containing ferroelectrics. However, the piezoelectric response of pure Bi0.5Na0.5TiO3 does not compare to the strong piezoelectric response of lead based piezoelectrics. To increase the piezoelectric response, Bi0.5Na0.5TiO3 has been alloyed with BaTiO3 and K0.5Na0.5NbO3. Another route to enhance the response is to take advantage of the anisotropic properties by inducing a preferred crystallographic orientation. Both routes were used to investigate the effect a crystallographic texture has on the strain response of Bi0.5Na0.5TiO3-based ceramics. A crystallographic texture was induced by templated grain growth of pure phase Bi0.5Na0.5TiO3 templates using the tape casting method to orient template particles relative to the tape cast normal. Sintered Bi0.5Na0.5TiO3 based materials developed a strong (00l)pc fiber texture relative to the tape cast normal, with no preferential alignment relative to the tape cast plane. Textured Bi0.5Na0.5TiO3-(5)BaTiO3 showed a piezoelectric response of 245 pC/N, a better than 50% enhancement from the 150 pC/N response of randomly oriented samples. The Bi0.5Na0.5TiO3-(x)BaTiO3-(y)K0.5Na0.5NbO3 (x,y) system has been shown to undergo electric-field-induced phase transformation from a pseudocubic to polar phase. For (7,2) a strong 8.67 multiples of a random distribution (MRD) crystallographic texture increased the macroscopic strain response by 50%. Applying the electric field perpendicular to the fiber texture axis reduces the macroscopic strain response of textured (7,2) by 17%. The affect field direction has on the electric-field-induced phase transformations of textured (7,2) was investigated using in situ electric field dependent diffraction. In situ diffraction data showed the high strain response of textured (7,2) can be attributed to a reversible pseudocubic to tetragonal transformation. The field-induced tetragonal phase nucleates preferentially with a strong c-axis alignment in the electric field direction, ferroelastic domain texture. In situ diffraction data suggests the origin of the reduction in strain associated with a field applied perpendicular to the fiber texture axis is the result of a shorter induced lattice spacing and lower domain texture. Date: Thursday, April 4, 2013 Time: 9:30 A.M. Place: HAMP 1113 Lisa Stacey Secretary/Development Assistant Purdue University School of Materials Engineering 765/494-4100

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Fwd: Call for poster presentation - 17th GLCACS Conference Meeting - May 4, 2013, Deerfield, IL
by Donna Bystrom 28 Mar '13

28 Mar '13

******************** Dear Ms. Cline, My name is Qing Xu. I work as a Sr. Engineer for UOP, A Honeywell Company in the north Chicago suburb. I am a committee member of GLCACS (Great Lake Chinese American Chemistry Society). We are holding the annual conference on May 4th in Deerfield, IL. We will have plenary speakers from major local corporations and will have student/post-doc poster competition. We will also have corporate career recruiting/consulting events at the conference. All the professors/post-docs/students in your department are welcome to participate. The registration is free. Could you kindly help me distribute conference and student poster competition announcements to people in your department? Thanks a lot! Attached please find our conference announcement flyer and poster/presentation competition application information. Detailed conference information and registration are also available at our website: http://www.greatlakecacs.org/index.html Thank you and have a good day. Qing Xu

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Fwd: FW: Physical Facilities Connection – March 28, 2013
by Donna Bystrom 28 Mar '13

28 Mar '13

<https://www.purdue.edu/pfcommunications/pf_connection/building_deputies.html> <http://www.purdue.edu/pfcommunications/forms/comm_request.php> *University-Wide News* Tippecanoe County Siren Testing this Saturday (March 30) <https://www.purdue.edu/pfcommunications/university_wide/news_events/siren_t…> Boilermaker Butcher Block <https://www.purdue.edu/pfcommunications/university_wide/campus_partners/but…> *Construction Notices* US 231 Lane Restrictions Begin Monday, Continue to August <https://www.purdue.edu/pfcommunications/construction_notices/us_231_lane_re…>

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FW: SEMINAR NOTICE: O. Keles, PhD Final Exam, Tue. 4/2/13, 8:30 am, ARMS 1028
by Stacey, Lisa A 27 Mar '13

27 Mar '13

MATERIALS SCIENCE AND ENGINEERING SEMINAR Modeling Failure of Brittle Porous Ceramics By: Özgür Keleş Ph.D. Final Examination Co-Advisors: Prof. R. E. Garcia & K. J. Bowman ABSTRACT Brittle porous materials (BPMs) are used for battery, fuel cell, catalyst, membrane, filter, bone graft, and pharmacy applications due to the multi-functionality of their underlying porosity. However, in spite of its technological benefits the effects of porosity on BPM fracture strength and Weibull statistics are not fully understood--limiting a wider use. In this context, a two-dimensional finite element (FE) simulation-based approach was developed to assess the pore--pore interactions and their impact on fracture statistics of isotropic microstructures. The classical fracture mechanics approach was combined with FE simulations that account for the interactions to predict the decrease in the fracture stress with increasing porosity. Simulations show that even the microstructures with the same porosity level and size of pores differ substantially in fracture strength. The maximum reliability of BPMs was shown to be limited by the underlying pore--pore interactions. BPM fracture strength decreases at a faster rate under biaxial loading than under uniaxial loading. Three different types of deviation from classic Weibull behavior are identified: P-type corresponding to a positive lower tail deviation, N-type corresponding to a negative lower tail deviation, and S-type corresponding to both positive upper and lower tail deviations. Pore-pore interactions result in either P-type or N-type deviation in the limit of low porosity. Whereas, S-type behavior occurs when clusters of low and high fracture strengths coexist in a fracture data. Date: Tuesday, April 2, 2013 Time: 8:30 A.M. Place: ARMS 1028 Lisa Stacey Secretary/Development Assistant Purdue University School of Materials Engineering 765/494-4100

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MSE 690 SEMINAR NOTICE: Dr. Frank Kustas, Mon. 4/1/13, 3:30 pm, ARMS 1010
by Stacey, Lisa A 25 Mar '13

25 Mar '13

Please see attached Seminar Notice/Abstract/Bio Info for our next visiting speaker, Dr. Frank Kustas. Please plan to attend. Thank you, Lisa Stacey Secretary/Development Assistant Purdue University School of Materials Engineering 765/494-4100

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Fwd: Post doc Buddy needed
by Donna Bystrom 22 Mar '13

22 Mar '13

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FW: SEMINAR NOTICE: P. Sarabol, PhD Final Exam, Thur. 3/8/13, ARMS 1103, 1:30 pm
by Stacey, Lisa A 21 Mar '13

21 Mar '13

Please see seminar notice below: MATERIALS SCIENCE AND ENGINEERING SEMINAR Effects of Local Grain Orientations and Grain Misorientations On The Nucleation and Growth of Tin Whiskers and Hillocks By: Pylin Sarobol Ph.D. Final Examination Co-Advisors: Prof. C. Handwerker and Prof. J. Blendell ABSTRACT Whiskers and hillocks grow spontaneously on Pb-free Sn electrodeposited films as a response to thin film stresses. Stress relaxation occurs by atom deposition to specific grain boundaries in the plane of the film, with hillocks being formed when grain boundary migration accompanies growth out of the plane of the film. The implication for whisker formation in electronics is serious: whiskers can grow to be millimeters long, sometimes causing short circuiting between adjacent components and, thereby, posing serious electrical reliability risks. In order to develop more effective whisker mitigation strategies, a predictive physics-based model has been needed. A growth model is developed, based on grain boundary faceting, localized Coble creep, as well as grain boundary sliding for whiskers, and grain boundary sliding with shear induced grain boundary migration for hillocks. In this model of whisker formation, two mechanisms are important: accretion of atoms by Coble creep on grain boundary planes normal to the growth direction inducing a grain boundary shear and grain boundary sliding in the direction of whisker growth. The model accurately captures the importance of the geometry of "surface grains"-shallow grains on film surfaces whose depths are significantly less than their in-plane grain sizes. A critical factor in the analysis is the ratio of the grain boundary sliding coefficient to the in-plane film compressive stress. If the accretion-induced shear stresses are not coupled to grain boundary motion and sliding occurs, a whisker forms. If the shear stress is coupled to grain boundary migration, a hillock forms. Based on this model, long whiskers grow from shallow surface grains with easy grain boundary sliding in the direction of growth. Other observed growth morphologies will be discussed in light of our model. Additional insights into the preferred sites for whisker and hillock growth were developed based on elastic anisotropy, local film microstructure, grain misorientation, and elastic strain energy density (ESED) as the driving force for growth. Local grain orientations and strains measured by synchrotron micro-diffraction in regions containing whiskers or hillocks were compared with elastic finite element analysis simulations, including Sn elastic anisotropy. Whisker and hillock grains were observed to have higher crystallographic misorientations with neighboring grains than generally observed in the microstructure. While elastic simulations predicted higher local out-of-plane elastic strains and ESEDs for whisker and hillock grains, synchrotron measurements of out-of-plane strains of whisker and hillock grains after growth showed relaxation, with correspondingly low ESEDs calculated from measured strains. This suggests that, before whisker or hillock formation, highly misoriented grains with high out-of-plane elastic strains and ESEDs relative to their neighbors determined, at least in part, which grains became whiskers or hillocks. Based on the models and experiments in this thesis, a clearer picture emerges of the necessary and sufficient conditions for tin whisker and hillock formation in thin films. Date: Thursday, March 28, 2013 Time: 1:30 P.M. Place: ARMS 1103 Thank you, Lisa Stacey Secretary/Development Assistant Purdue University School of Materials Engineering 765/494-4100

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FW: SEMINAR NOTICE: S. Dubelman, PhD Final Exam, Thur. 3-28-13, 7:30 am, ARMS 1028
by Stacey, Lisa A 21 Mar '13

21 Mar '13

Please see seminar notice below: MATERIALS SCIENCE AND ENGINEERING SEMINAR Failure Analysis of Micron Scaled Silicon Under High Rate Tensile Loading By: Steven J. Dubelman Ph.D. Final Examination Advisor: Prof. W. Chen ABSTRACT Structures have been built at micro scales with unique failure mechanism not yet well understood, in particular, under high-rate loading conditions. Consequently, MEMS devices suffer from inconsistent performance and insufficient reliability. This research aims to understanding the failure mechanisms in micro-scaled specimens deforming at high rates. Single crystal silicon micro beams that are 4 microns thick are subjected to tensile loading at average strain rates of 100 s-1 using a miniature modified Kolsky tension bar. A capacitance displacement system and piezoelectric load cell are incorporated to measure the strain and stress of the silicon micro beams directly to ensure precision. Extreme fragmentation of the beams occurs during failure and this phenomenon is observed using a high speed camera. A debris retention system is used to capture the silicon fragments for direct inspection using a Scanning Electron Microscope. The failure mechanism of the micro beams is attributed the presence of multiple micron scaled surface defects rather than any one large critical flaw. Date: Thursday, March 28, 2013 Time: 7:30 A.M. Place: ARMS 1028 Thank you, Lisa Stacey Secretary/Development Assistant Purdue University School of Materials Engineering 765/494-4100

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FW: Winchell Seminar Reminder - P. Sanders, Fri., 3/22/13, 3:30 pm, ARMS 1010
by Stacey, Lisa A 21 Mar '13

21 Mar '13

Reminder: Tomorrow is our next Peter Winchell Lecture Series Seminar, featuring Prof. Paul Sanders from Michigan Tech University. Please plan to attend. Thank you, Lisa Stacey Secretary/Development Assistant Purdue University School of Materials Engineering 765/494-4100

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Fwd: RE: Physical Facilities Connection – March 21, 2013
by Donna Bystrom 21 Mar '13

21 Mar '13

All, I have contacted Parking Facilities for additional information concerning the PGNW entry closure taking place tomorrow afternoon; it is the northern-most entry on the Northwestern side of the structure. All other entries will be open as usual. Thanks, Donna Ahlen _ ________________________________ _ <https://www.purdue.edu/pfcommunications/construction_notices/pgnw_entrance_…>

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