1. Direct Observation of Ideal Strength in Gum Metal Daryl C. Chrzan, University of California-Berkeley, DMR 0706554 It is a remarkable fact of nature that the mechanical strength of most materials falls far short of their potential maximum, their so-called ideal strength. Recently, Toyota introduced a Ti-Nb based alloy that was claimed to deform at stresses approaching its ideal strength. Further, the deformation mechanism appeared to be very unusual involving neither dislocations nor phase transformations. These claims were met with some skepticism. After all, if the claims are verified, Gum Metals are the first known example of a bulk engineering alloy with mechanical properties controlled by ideal strength, and have the potential to usher in a new era of alloy design. We have used nanoindentation within a TEM to establish unequivocally that nanopillars of Gum Metal can deform at stresses nearing their ideal strength. Further, though a phase transformation is observed, it is manifestly incidental to the observed deformation. The figure shows diffraction patterns (a-f,i,j), engineering tensile stress vs. displacement (g), and TEM images of the pristine (h) and deformed (k) Gum Metal nanopillars. The arrows in (b-f) highlight spots associated with the phase transformation. Note that the spots appear at (b) before yield (between c and d), and their intensity remains weak throughout deformation. The observed tensile stress (g) resolves to 1.7 GPa of shear stress for this pillar. The ideal strength of the alloy is 1.7-1.9 GPa. Comparison of initial diffraction (i) with final (j) reveals substantial rotation of the sample during deformation.

2. Physics and Materials Science of Skateboarding Daryl C. Chrzan, University of California-Berkeley, DMR 0706554 An outstanding challenge to Materials Science and Engineering as a discipline is to make high school students aware of its existence and importance before they arrive on college campuses. To address this need, we are developing educational materials suitable for incorporation into high school physics courses. The sport of skateboarding is used to highlight the importance of materials properties to function, and to introduce very basic ideas in materials science. Topics covered include rolling friction (bearing and wheel materials) and bending strength (wood). Each topic considered incorporates a simple experiment and accompanying analysis. The course materials are developed within the context of a freshmen seminar series course at UC Berkeley. The seminar is offered to the broader campus community, and includes a students with majors in a wide variety of disciplines. So far, the course has been taught two years, and has been well received. (See http://www.wired.com/beyond_the_beyond/2009/08/without-urethane-skateboarding-would-have- faded-into-obscurity/ for an article describing the most recent offering.) This year, we intend to expand the number of experiments, and refine the teaching materials. We plan to release the materials to high school teachers the following year.http://www.wired.com/beyond_the_beyond/2009/08/without-urethane-skateboarding-would-have- faded-into-obscurity/ Analysis of forces acting on a skateboard.