The overall goal of the project is to build and integrate knowledge of materials science and fracture mechanics to aid in the optimization of existing light metal alloys and the development of new and lighter alloys for fatigue and fatigue crack growth (FCG) performance in structural applications. The research will also provide methods and tools for improved design and fatigue life predictions. During the 1 st year, significant steps were taken towards achieving these goals and disseminating the knowledge through publications and to industry. Highlights of the accomplishments include: Generating reliable FCG data and establishing FCG mechanisms at the micro-/nano-structural scale of various cast and wrought Al alloys, at all growth stages; Building two-parameter design maps, correlating loading conditions (ΔK, K max, R), crack propagation modes, and materials’ microstructures to be used in component design, performance evaluation, and material/process optimization; Developing an original model to relate the effects of crack size and material microstructure to the FCG response and a unified method to predict FCG data/behavior (without testing). These developments will facilitate the design of higher-performance, safer, and more reliable vehicles; enable weight reduction; and contribute to reductions in fuel consumption and CO 2 emissions. CAREER: On the Engineering of Light Metals for Enhanced Dynamic Properties and Fatigue Performance Diana A. Lados, Worcester Polytechnic Institute, DMR The novel “small crack growth model” developed (below) and model validation on the A535-F alloy (above right) i=n i=2 i=1 Intergranular Mode Mixed Mode Transgranular Mode Test End Intergranular Mode R=0.1 Mixed Mode Transgranular Mode i=3 Changes in the FCG mechanisms at the microstructural scale of as-cast Al-7%Mg alloy (A535-F); optical side view (above), SEM top view (left), two-parameter design map (below left)

Educational outreach programs have been designed and implemented to develop appreciation and interest in science and engineering and materials science. These programs engaged high school students and girls ages 9-13 to positively affect their understanding of our field and career choices, and they include: Creating a new learning module on “Fatigue and Fracture of Metallic Materials” for the ASM New England Materials Experience/Camp (first offered in May 2013 to a group of 80 high school students and teachers); Initiating a “Young Women in Science” summer program for girls grades 5-7 to introduce them to materials science and engineering at early stages (first offered in July 2013 to 40 young girls). Both programs will be continued yearly. Additional avenues for disseminating the knowledge developed through this research include the Integrative Materials Design Center (iMdc) at WPI, an industry-government-university consortium, founded and led by the PI, with members from all transportation sectors, national labs, and government, and a senior Aerospace Materials course developed and taught by the PI. Photos: ASM Materials Camp students participate in the “Fatigue and Fracture” module (top), “Young Women in Science” camp students spend a day learning about materials and taking part in hands-on demonstrations (center), and Spring iMdc consortium meeting participants, June 2013 (bottom) CAREER: On the Engineering of Light Metals for Enhanced Dynamic Properties and Fatigue Performance Diana A. Lados, Worcester Polytechnic Institute, DMR