OREGON STATE UNIVERSITY
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At microstructural level, different phenomena occur in the material during a manufacturing process. Recrystallization, grain growth, formation and development of crystallographic texture, phase transformation, precipitation or dissolution of secondary phases are common examples. A fascinating aspect of our research is to understand driving forces of these phenomena and the relationship with manufacturing parameters and eventually engineer the microstructure so the part shows the desired performance in service. As an example, the figure (link to the journal article) shows the evolved texture and formation of Martensitic morphology in Ti sheet processing.
In the Laboratory of Materials and Manufacturing, we apply numerical methods and develop new algorithms to discover and understand the thermodynamics, kinematics and dynamics of emerging manufacturing technologies. A fundamental understanding of the physics and mechanics of the process is crucial in expanding the boundaries of manufacturing technologies towards new materials, geometries and shapes and also to superior performance of the part. As an example, the figure (link to the journal article) shows the flow diagram of an algorithm developed for shear angle determination in hard metal machining. In this area, analysis of residual stresses developed in manufacturing processes, is another research focus of our lab.
A fascinating side of our research in the laboratory of materials and manufacturing, is to understand the physical and mechanical phenomena that govern the relationship between structure, property and processes. The outcomes of these research efforts are essential in design of new materials with novel thermophysical and mechanical behavior. As an example, (link to the journal article) the figure shows the mechanical failure modes as well as the mechanically stable fields of a metal matrix composite, as function of distribution of secondary phase strengtheners.
Another aspect of our research is developing algorithms for computational determination of thermophysical properties composites. We consider the shape, distribution, volume fraction of constituent phases as well as, the manufacturing parameters and other parameters, in order to determine if the composite's service response meets or excels the requirements of the application(s). As an example (link to the journal article), the figure shows a digital block of porous of Ni-YSZ composite, with energy and fuel cell applications, and the corresponding temperature-dependent thermal conductivity predicted by our algorithm and verified by experimental results.
An important aspect of our research is to understand the relationship between field variables (i.e. strain, stress, temperature, etc.) in the material, by developing rigorous constitutive laws that capture this relationship closely. Knowledge of accurate constitutive laws is crucial in successful implementation of any manufacturing technology and delivering the final part with desired performance. As an example, the figure shows (link to the article) a newly developed rate and temperature dependent constitutive law for Ti alloys closely agrees with experimental observations.
