Introduction

“More than any other attribute, microstructure exerts a controlling influence over the final properties and performance of a material. With clear interpretation and a sound understanding, microstructure can be exploited to provide outstanding mechanical, electrical, magnetic, or chemical properties. Conversely, insufficient attention to control of microstructure can lead to unpredictable properties, inconsistent behavior, and material failure”, commented Ryan M. Deacon, editor of Metallography, Microstructure, and Analysis (MMA), in the journal’s inaugural issue [1].

Materials are a critical component to the development of new technologies, and an understanding of new microstructures is critical to material development. In response to the increasing importance of advanced material development and evolved technology, the U.S. government launched the Materials Genome Initiative (MGI) in 2011, with the goal of providing a framework to support discovery, manufacturing, and deployment of advanced materials “twice as fast, at a fraction of the cost” [2]. Access to microstructure data linked to process and property data supports the goals of MGI, and the ASM Micrograph Database has the potential to help fulfill this need.

Background

This database, originally named the ASM Micrograph Center, was developed in 2003 and 2004 under the guidance of an ASM editorial advisory committee with input from other interested member groups, including the International Metallographic Society (IMS), the ASM Materials Properties Database Committee (MPDC), and the ASM Technical Books Committee. The initial collection was made possible thanks to broad-based involvement by members of ASM International who participated in the contribution and review of micrographs and supporting data. Today, the collection is a dynamic database [3–5] that will continuously expand to meet the changing needs of current and future ASM members, and anyone interested in the art and science of metallography and material characterization.

Using the Database

From the Micrograph Database product homepage (Fig. 1), users can easily search and browse the entire database, and link to additional information of interest. The toolbar includes a Quick Search feature and a link to the Advanced Search page. The left panel contains the general schema represented as a tree-like structure, allowing users to browse the database by material category. The right panel features an image carousel, providing prospective consumers with a snapshot view of example micrographs. The homepage also includes quick links to more detailed information about the database, new content additions, micrograph submission and subscription details, and feedback. The Advanced Search function (Fig. 2) provides an easy way for users to find micrographs of interest by specifying multiple criteria. A pre-defined search feature enables users to quickly select specific conditions, product forms, and material groups to find micrographs meeting those criteria.

Fig. 1
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Homepage of the ASM Micrograph Database

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Fig. 2
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Example of an Advanced Search

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Organization of the Database

The database has been organized into three separate tables:

  • Micrograph data table—Contains high-resolution images and all pertinent details about the micrographs,

  • Micrographs table—Groups all similar materials together so that users can see the data in an organized fashion,

  • Micrograph Series table—Contains images submitted together, which tells the story about a specific grade of a material.

The tables seamlessly interact with each other, providing the best possible user experience (Fig. 3). General schema seen in the left tree panel and database record counts by material category, are shown below and in Figs. 4 and 5:

  • General (7 records)

  • Ceramic (198 records)

    • General (7)

    • Boride-base material (1)

    • Carbide-base material (47)

    • Nitride-base material (12)

    • Oxide-base material (131)

  • Composite (189 records)

    • Natural (6)

    • Polymer matrix (183)

      • General (129)

      • Thermoplastic matrix (21)

      • Thermoset matrix (33)

  • Ferrous (2183 records)

    • General (1)

    • Cast iron (298)

    • Iron alloy (40)

    • Iron-base superalloy (33)

    • Steel (1811)

  • Non-ferrous (1490 records)

    • Al (426)

    • Co (4)

    • Cu (447)

    • Pb (34)

    • Mg (52)

    • Miscellaneous (28)

    • Ni (27)

    • Refractory and reactive (56)

    • Superalloy (135)

    • Ti (261)

    • Zn (26)

  • Polymer (1 record)

At the record level, the following attributes have been assigned:

  • Micrograph image (including image name and scale),

  • Material details (name, type, alternate names, composition, condition, product form, properties, description),

  • Image details (image code, photo method and details, etchant, original magnification),

  • Links to a series, if applicable,

  • Links to a summary table containing all micrographs showing the same material, if applicable,

  • Keywords,

  • Contributor information,

  • Source details.

Fig. 3
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Structure diagram of the ASM Micrograph Database

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Fig. 4
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Attributes at record level

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Fig. 5
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Some record attributes (right panel) for Martensitic stainless steel—420. Microstructure at the surface of a decarburized, hardened specimen. Note the free ferrite (arrows) at the surface (complete loss of carbon) and the change in the appearance of the martensite in the partial decarburized zone

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Summary Table

The “Micrographs” table groups similar materials together so that users can view the data in an organized fashion. Figure 6 illustrates how a few natural composites are grouped together in a summary table. Each individual record from the summary table will lead to the record itself and its specific attributes.

Fig. 6
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Example of a summary information table that appears once the user clicks on the record attribute “All micrographs for this material”

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Micrographs Series Table

The “Micrograph Series” table contains images submitted together, which tells the story about a specific grade of a material. Figure 7 shows 3 individual records of thermoplastic matrix carbon fiber reinforced all linked as a series.

Fig. 7
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Example of a Series table that appears once the user clicks on the record attribute “All micrographs from this series”, series link

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Software Platform

The original software for the application was developed by Granta Design, based on their Cambridge Engineering Selector (CES) software. The software platform was upgraded from CES to GRANTA MI version 6 in 2013, and to MI version 7 earlier this year. In addition to general performance and usability improvements, the latest version of the software includes enhancements specific to the Micrograph Database. The search improvements are the most significant. A Quick Search for Stainless Steel, for example, provides a total of 139 results, 133 results in the Micrographs Data table, and 6 results in the Micrograph Series table. After running a search, a user can click on any record to view the specific record details (Fig. 8).

Fig. 8
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The results of a search for Stainless Steel

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Future Direction

The ASM Micrograph Database currently represents an authoritative, comprehensive library of micrographs and related data used by industry, academia, and government. Near-term content additions will include a selection of micrographs from the Metallography, Microstructure, and Analysis (MMA) journal, published by Springer, plus peer-reviewed database submissions. The Computational Materials Data Network initiative—founded by ASM—and associated projects may provide future content for the Micrograph Database, and new ways to utilize the data to support advanced material research and development.