MAE Special Seminar--Microparticles Under Extreme Impact Conditions

Location

106 Upson Hall

Description

When microparticles impact solid materials at high velocities, a variety of fundamental phenomena can occur, including plasticity, solid-state bonding, phase transformation, chemical reaction, and erosion. The conditions required to effect these various phenomena are known rather imprecisely because of limitations on experiments designed to study them. This talk will survey my recent work using a new in-situ test methodology to launch, observe, and study individual microparticle impacts, at micrometer length-scales and nanosecond timescales. I review extreme mechanics and physics of materials in a space defined by ~10 μm particle size and up to ~1.5 km/s particle velocity. Combining real time observations and post-mortem characterizations with theoretical development and modeling, I review in details how the input kinetic energy is dissipated, from plasticity to solid-state bonding, to impact-induced melting, and eventually to extreme failures. While plastic deformation and failures are at the heart of fundamental solid mechanics, solid-state bonding at micron-scale provides a ground for advanced/additive manufacturing, and impact-induced melting opens new opportunities in mechanochemistry.

Mostafa Hassani-Gangaraj is a Postdoctoral Associate in the Department of Materials Science and Engineering at MIT. He received his PhD with the highest honors in Mechanical Engineering from Polytechnic University of Milan in 2014. During his PhD, he applied impact to create gradient nanostructures in metallic materials, and enhanced their fatigue performance. In 2015, he joined Prof. Schuh’s group at MIT where his current focus is to fundamentally understand impact-induced extreme conditions in microparticles, and to exploit them as a basis for solid-state advanced/additive manufacturing. Mostafa was awarded the Roberto Rocca Postdoctoral Fellowship, Acta Materialia outstanding reviewer award, and the “Nanotechnologies and Nanostructured Innovative Materials” award. His recent results on microparticle impact were featured on the MIT News page and other news outlets. Invited by the Army Research Laboratory, Mostafa is currently co-editing a book on additive manufacturing processes that rely on impact bonding.