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Ph.D. and Post-doc opportunities in ‘Small-scale mechanics and advanced microstructural characterizations’ at Texas A&M

Dr. Kevin Xie's group at Texas A&M is planning to recruit two Ph.D. students and a postdoctoral research fellow starting 2018.

 

The overarching aim of the research projects is to understand mechanics of materials at nano- and sub-micron scales by applying advanced microstructural characterization techniques such as Cs-corrected STEM, TEM- based orientation mapping, EELS, and atom probe tomography. The details of the projects are as follows:

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Call for Abstracts: SES2016 Symposium D-6: Advanced Instrumentation and Fabrication Techniques for the Measurement of Mechanical and Physical Properties of Solids and Structures

Dear Colleagues,

The 53rd Annual Technical Meeting of the Society of Engineering Science (SES2016) will be hosted by the University of Maryland (UMD) during 2-5 October 2016 at the College Park Marriott Hotel & Conference Center. 

We would like to invite you to submit abstracts for our symposium entitled “Advanced Instrumentation and Fabrication Techniques for the Measurement of Mechanical and Physical Properties of Solids and Structures”

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High-temperature tensile behavior of freestanding Au thin films

In this paper, the mechanical behavior of freestanding thin sputter-deposited films of Au is studied at temperatures up to 340°C using tensile testing. Films tested at elevated temperatures exhibit a significant decrease in flow stress and stiffness. Furthermore the flow stress decreases with decreasing film thickness, contravening the usual notion that “smaller is stronger”. This behavior is attributed mainly to diffusion-facilitated grain boundary sliding.

This paper has been accepted by Scripta Materialia.

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Fatigue of polymer-supported Ag thin films

The fatigue behavior of Ag films on polyethyleneterephthalate substrates was studied using electrical resistance measurements.
Scanning electron microscopy images showed two types of failure: typical fatigue failure with extrusion–intrusion pairs, and ductile
failure with local necking. Once through-thickness cracks are formed in the metal layer, cracks propagate and the resistance increases abruptly for both failure modes. The effect of adhesion on fatigue life is discussed in terms of concurrent delamination, crack initiation and propagation.

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Improving the stretchability of as-deposited Ag coatings on poly-ethylene-terephthalate substrates

In this paper, we report that silver films evaporated on poly-ethylene-terephthalate (PET) substrates coated with an acrylic primer can be stretched beyond 70% without fracture. As-deposited films show a larger failure strain than annealed coatings. These observations are rationalized in light of a ductile fracture mechanism where debonding from the substrate coevolves with strain localization. The results of this study indicate that PET substrates coated with an acrylic primer layer may be suitable for stretchable electronics.

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