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An Examination of Abnormal Grain Growth in Low Strain Nickel-200

Metallography, Microstructure, and Analysis

Laros, James H.; Madison, Jonathan D.; Thompson, G.B.; Welsh, S.; Evans, J.

This study offers experimental observation of the effect of low strain conditions (ε < 10%) on abnormal grain growth (AGG) in Nickel-200. At such conditions, stored mechanical energy is low within the microstructure enabling one to observe the impact of increasing mechanical deformation on the early onset of AGG compared to a control, or nondeformed, equivalent sample. The onset of AGG was observed to occur at specific pairings of compressive strain and annealing temperature and an empirical relation describing the influence of thermal exposure and strain content was developed. The evolution of low-Σ coincident site lattice (CSL) boundaries and overall grain size distributions are quantified using electron backscatter diffraction preceding, at onset and during ensuing AGG, whereby possible mechanisms for AGG in the low strain regime are offered and discussed.

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TYPE Journal Article YEAR 2016
DOIOSTIScopus

Integrated Computational Materials Engineering: Tools, Simulations and New Applications

JOM

Madison, Jonathan D.

Here, Integrated Computational Materials Engineering (ICME) is a relatively new methodology full of tremendous potential to revolutionize how science, engineering and manufacturing work together. ICME was motivated by the desire to derive greater understanding throughout each portion of the development life cycle of materials, while simultaneously reducing the time between discovery to implementation [1,2].

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TYPE Journal Article YEAR 2016
DOIOSTIScopus

Predicting mesoscale microstructural evolution in electron beam welding

JOM. Journal of the Minerals, Metals & Materials Society

Rodgers, Theron R.; Madison, Jonathan D.; Tikare, Veena T.; Maguire, Michael C.

Using the kinetic Monte Carlo simulator, Stochastic Parallel PARticle Kinetic Simulator, from Sandia National Laboratories, a user routine has been developed to simulate mesoscale predictions of a grain structure near a moving heat source. Here, we demonstrate the use of this user routine to produce voxelized, synthetic, three-dimensional microstructures for electron-beam welding by comparing them with experimentally produced microstructures. When simulation input parameters are matched to experimental process parameters, qualitative and quantitative agreement for both grain size and grain morphology are achieved. The method is capable of simulating both single- and multipass welds. As a result, the simulations provide an opportunity for not only accelerated design but also the integration of simulation and experiments in design such that simulations can receive parameter bounds from experiments and, in turn, provide predictions of a resultant microstructure.

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TYPE Journal Article YEAR 2016
DOIOSTI
Results 101–125 of 166
Results 101–125 of 166