The properties of metals and their alloys depend strongly on their processing history. The conditions under which materials are processed and fabricated into useful items determine the distributions of phases, grains, and defects in the final products. These distributions are crucial in determining the alloy strength, ductility, magnetic response, homogeneity, and other properties important for commercial applications. The Metals Processing Program focusses on measurements and predictive models needed by industry to provide improved process control, develop improved alloy properties, tailor material properties for particular applications, and reduce costs.

Major successes in applying measurements and modeling to processing applications already have been achieved, notably in interactions with the aerospace, powder metallurgy, and electronic industries. For example, cooperative research and development projects with industry (Crucible Compaction Metals, Fluxtrol Manufacturing) have resulted in significant improvements in process control for steel and superalloy powders. Moreover, predictive models for solidification and microstructural evolution during processing have been incorporated by industry into design systems for casting of aerospace alloys and production of defect-free electronic materials, helping to reduce rejection rates arising from defective parts. Current measurement and modeling activities in this program emphasize work on rapidly solidified steels, aerospace castings, thin films, intermetallic alloys and electronic materials. Frequent interactions and collaborations with industrial producers are maintained, including participation in industrially-oriented consortia and the American Society for Testing and Materials (ASTM). Standard reference materials, such as the homogeneous standard reference materials currently being produced by rapid solidification, which are unobtainable by other means, are another important output of the current work.

Measurements and predictive models for processing being pursued in this program are of three kinds:

• Measurements and models are developed to help design materials production processes, such as measurements and evaluations to provide alloy phase diagrams, which are the roadmaps alloy designers use to predict the alloy phases that can be produced under specific processing conditions. These evaluations are playing key roles in NIST collaborations with industrial consortia on electronic solders and casting of superalloys for aerospace applications.

• Measurements are made under dynamic conditions to monitor, in real time, properties of materials while they are actually being produced and to determine difficult-to- measure process parameters while the process is occurring. In collaboration with the NIST program on intelligent processing of materials, special fast-response sensors, simulations and imaging techniques have been developed for this purpose, and workshops have been held to transfer these techniques to industry. Here, dynamic models of the process are important both for design of manufacturing procedures and for applications of real time feedback and control.

• To evaluate the adequacy of process models, it is important to measure the properties of the final materials and relate them to the process conditions. A current emphasis in this respect is on relating impact resistance and corrosion resistance of rapidly solidified nitrogenated stainless steels to processing conditions and alloy microstructure. Norfolk Southern (railroad switches), Department of Defense (DoD)/ARPA (armor applications), and Crucible Materials Corporation (corrosion resistant alloys) have collaborated with NIST in various aspects of this work.

In all of this work, the goal is to help U.S. industry apply measurements and predictive modeling to produce improved materials at reduced cost.

Projects

Microhardness Standards
Processing of Advanced Materials
Solidification Modeling
Modeling and Simulation of Materials Processing
Electrodeposition of Alloys

For additional information about the Metals Processing Program, contact John R. Manning at 301-975-6157 or e-mail to manning @enh.nist.gov.

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Last modified: Mon Jan 06 09:46:15 1997 Metallurgy Webmeister