Professor Vlassak studies the thermo-mechanical behavior of a broad range of engineering materials. He has developed experimental methods to characterize phase transitions and solid-state reactions in thin films, plastic deformation of coatings, elastic anisotropy in indentation, and fracture of thin films. Current experimental research projects focus on the mechanical behavior of hydrogels (Figure 1, 2) and the use of hydrogels as ionic conductors in 3D printed devices (Figure 3). Recently, Professor Vlassak pioneered the use of combinatorial nanocalorimetry (Figure 4) for the development and analysis of complex materials systems, including metallic glasses, ultra-high temperature ceramics (Figure 5), and high-temperature shape memory alloys. Combinatorial nanocalorimetry provides a convenient way of mapping the energetics and kinetics of phase transitions and solid-state reactions as a function of composition, making it an ideal experimental tool for the Materials Genome Project (Figure 6). The technique also lends itself for the characterization of thermal fatigue and stability of functional materials, as well as for the optimization of heat treatments.
Past research projects focused on the mechanical degradation of electrodes in lithium ion batteries as a result of lithium insertion, on the effects of microstructural length scales on the mechanical behavior of thin metal films, and on the effect of chemical species on the adhesion and delamination of multilayered structures containing low-k dielectrics.
Theoretical work includes modeling of chemical mechanical polishing (CMP) based on contact mechanics, channel cracking in films on substrates of finite thickness, and various analyses of the effects of substrate properties and film porosity on nanoindentation of thin films.
Surface and Interface Science
Outside professional activities
Outside Professional Activities
In the spirit of transparency and integrity, Salata Institute Faculty Associates disclose publicly their key professional activities outside of Harvard University. The activities disclosed below are for the most recent reporting period, as defined by University policy. Some of the activities may be paid, some may be unpaid, and others may be in exchange for expense reimbursement only.
Outside Professional Activities For Joost Vlassak
Professional jury or exhibition
Silicon Light Machines