Search Results for microstructure

An in-situ annealing technique combined with electron backscatter diffraction was used to characterize the microstructural evolution of ZE20 magnesium alloy as a function of temperature. This work sets the stage for future experiments to understand and control the recrystallization behavior of commercial alloys.

This article identifies several factors that are not fully addressed in most fracture toughness test standards and explains how they may influence calculated values obtained from ferritic steels. Of particular consequence are test temperatures within the ductile-to-brittle transition regime and test specimen geometries when measuring the toughness of weld metal and heat-affected zones.

Research conducted at a brass-strip plant in Zutphen, Netherlands shows how nonlinear modeling can be used to predict the grain size and hardness of annealed strip based on composition and process variables. Production data gathered over the course of a year were used to train a feed-forward neural network that achieved a correlation coefficient of more than 86% when presented with new input data. The standard deviation between predicted and measured grain size was about 4.2 µm.

Characterizing ice and snow is important not only for building accurate climate models, but also for activities such as relating the mechanical properties of sea ice to its microstructure so that the interaction of ice with ships and structures can be better understood. This article describes the microstructural characterization of ice. Many microstructural characterization techniques that can be applied to other materials also can be used to examine ice.

This article demonstrates the application of machine learning to the classification and segmentation of bainitic microstructures and compares three approaches for assigning the ground truth: correlative microscopy using EBSD as an additional information source, comparison with images obtained from specially produced reference samples, and unsupervised learning.

Vision-based machine learning systems for microstructural characterization and analysis are being successfully used for image classification, semantic and instance segmentation, and object detection, leading to accurate, autonomous, objective, and repeatable results.

This entry won the prestigious Jacquet-Lucas Award for Best in Show in the 2020 International Metallographic Contest. In the research discussed in this article, light microscopy was applied to a Co28Cr6Mo alloy for a biomedical application processed by laser bed powder fusion (LPBF) additive manufacturing.

The rapidly increasing complexity of microelectronic devices is necessitating the use of sophisticated imaging tools to analyze and correct defects. This article describes advanced analytical techniques in use at the Fraunhofer Center for Applied Microstructure Diagnostics.

In order to take full advantage of the promise of recent computational efforts, new microstructural models that consider realistic shapes, connectivities, and distributions are required. Characterizing materials in 3D is necessary to reveal the actual distributions of relevant microstructural characteristics and thereby enable development of realistic models to predict the behavior of new materials. This article describes methods to model grain size distributions and presents case studies in cementite precipitation morphology and coarse martensite analysis.

This article describes research at Los Alamos National Laboratory that is aimed at building a coupled experimental and computational methodology that supports the development of predictive damage capabilities by: (1) capturing real distributions of microstructural features from real material and implementing them as digitally generated microstructures in damage model development, and (2) distilling structure-property information to link microstructural details to damage evolution under a multitude of loading states.

This work shows how metallographic analysis combined with energy dispersive X-ray spectroscopy helped investigators determine the basic processing techniques used in a circa 1910 silver-plated brass trombone, specifically, the joint between the mouthpiece receiver and a brace. This entry won the 2011 International Metallographic Contest sponsored by the International Metallographic Society.

Identifying metallographic TSC artifacts, specifically in air plasma spray zirconia-based thermal barrier coatings.

As high-entropy alloys become more complex in terms of microstructure, phase stability, and intermetallics, the advent of sophisticated analytical instruments is helping scientists to develop new materials with the most desirable properties. The analysis techniques described in this article include electron energy loss spectroscopy, electron probe microanalysis, atom probe tomography, and x-ray absorption spectroscopy.

This article explains how SEM, TEM, and atom probe tomography are being used in the development of additively manufactured high-entropy alloys (HEAs), revealing critical features such as anisotropic microstructure and metallurgical defects. It also discusses ongoing efforts to improve the predictability and analysis of HEA microstructure using data-driven approaches.

This article describes a procedure for optimizing the annealed microstructure of a high Al KAB steel. The main focus is directed toward characterization of microstructural development during annealing of different phases in a nanostructured bainitic steel using high resolution transmission electron microscopy (HRTEM). This entry won the prestigious 2019 Jacquet-Lucas Award for Excellence in Metallography at the International Metallographic Contest held in Portland, Oregon, October 2019.

Hot section components of next-generation energy systems call for superalloys that can handle the heat. This article describes some recent advances in superalloy research and development, including characterization and modeling tools that are key to developing and understanding the formation of new superalloys capable of withstanding extreme environments.

Flash processing, a new heat treatment for steels based on the concept of rapid thermal cycling, has been shown to achieve new levels of strength and ductility. This article describes the process, its effects on microstructure, and the phase transformations involved. It also discusses current and potential future applications.

A microscale fatigue testing technique for characterizing mechanical response and relating it to microstructure promises to improve fatigue life prediction for turbine engine components.

X-ray microscopy (XRM) offers long working distances and switchable magnification, facilitating time-resolved volumetric investigation of materials and structures. Examples show how XRM opens new windows into microstructure evolution processes in functional materials such as batteries, in response to charge state, and polymer foams, in response to compression loading.

Using advanced characterization techniques on surface hardened steels builds a richer understanding of the underlying metallurgical phenomena.