This article, the second in a two-part series on titanium alloys, examines the effects of microtexture on deformation behavior, slip dislocations, and fatigue properties. Part I, which appeared in the April 2021 issue, described microstructural evolution processes that result in microtexture formation.

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

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 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.

This primer discusses three image-based methods that simplify the analysis of phase composition, porosity, and particle distribution, thus providing additional insight into the microstructure of materials.

Structural features, spatial locations, and morphological measures not readily attainable with 2D methods are now accessible using 3D microstructure characterization techniques.

For parts made by direct metal laser melting, heat treatment is important to set the final microstructure, which impacts mechanical properties.

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.

A new process called nanofunctionalization was successfully used to control the solidifying microstructure during additive manufacturing and produce crack-free 7000 and 6000 series aluminum alloys for the first time.

Production techniques based on net shape forming from the liquid or semisolid state offer advantages in terms of manufacturing simplicity, cost, and energy consumption compared with current complex solid state forming processes. Engineering molten alloys to change their solidification process improves part integrity and alloy microstructure, leading to better component performance.

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 presents a broad overview of key annealing processes such as recovery, recrystallization, and grain growth in magnesium and its alloys. It explores the role of recovery in recrystallization behavior, evolution of recrystallization microstructure and texture, current understanding of grain coarsening in magnesium alloys, and concludes with a perspective on future research.

In order to expand the choice of materials available for use in additive manufacturing, parameters that consider welding metallurgy, laser powder interaction, and post processing must be developed. This article describes the outcomes of process development for a steel and stainless steel alloy that are not standard materials for laser powder bed fusion equipment.

Although the widespread use of titanium alloys is constrained by high costs, powder metallurgy techniques such as additive manufacturing (AM) represent an economical approach to fabricating titanium components. Various approaches to AM, along with examples of components made by different AM processes, are presented. The microstructures and mechanical properties of Ti-6Al-4V produced by AM are also discussed and compared with cast and wrought products. Finally, the economic advantages of AM compared to conventional processing are presented.

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.

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.

Outdoor enclosures for telecom equipment are often constructed from powder-coated aluminum, but with appropriate surface treatments, hot and cold rolled steel can serve in the same capacity at a lower cost. This article, the first of a two-part series, discusses the intrinsic corrosion behavior of hot and cold rolled steel and how it can be modified through galvanizing and aluminizing treatments. Part 2, scheduled for the October 2012 issue of AM&P , covers nonmetallic surface treatments and presents corrosion test results.