Material science undergraduate student Moriah Bischann, mentored by aerospace postdoctoral scholar, Dr. Owen Kingstedt, is the winner of the Doris S. Perpall Summer Undergraduate Research Fellowships (SURF) Speaking Competition. She was recognized as the best speakers-out of the 200 students who presented their SURF research. Her summer research focused on exploring the next generation of structural materials. During her ten week SURF project she studied the effects of alloying and processing on the dynamic behavior of magnesium (Mg). This work was done to address the larger question of whether Mg is a useful material for the automotive, aerospace, energy, and defense industries where a material is needed that has low density, but also the strength to withstand high impact forces.
Moriah’s SURF project was entitled, “High Strain-Rate Dynamic Behavior of Magnesium and AZ31B.” Magnesium’s implementation as a light weight structural material has lagged because its hexagonal-close-packed (HCP) crystal structure leads to complex deformation response. Within this work she examined the high strain-rate (102 to 103 s-1) dynamic response using the split-Hopkinson pressure bar. Experiments were conducted using specialized striker bars to promote a constant strain-rate, strain-rate increment, or strain-rate decrement during a single loading event. Thermo-mechanically processed magnesium (Mg) and Mg alloy AZ31B were examined along various loading directions to explore the strain-rate sensitivity of the different deformation mechanisms, such as deformation twinning or basal slip, which occur under a prescribed loading condition. The results of these experiments capture the anisotropic material response of Mg and AZ31B with respect to loading orientation.
Robert C. Perpall, a Caltech mechanical engineering alumnus and past member of the SURF Board, created the Doris S. Perpall SURF speaking prize in 1993 as an incentive for Caltech students to give excellent oral presentations. [Speaker competition rating criteria]