Taleff Research Group: Projects

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Enhanced Tensile Ductility in Aluminum Alloys

Sponsor: National Science Foundation, CAREER Grant

This four-year, funded program addresses the experimental investigation of mechanical behavior in aluminum-based alloys at elevated temperatures. The goal of this program is to develop a quantitative understanding of mechanical behavior in ternary alloys using composition, processing, and microstructure to explain and predict behavior. This work is expected to lead to new aluminum materials which exhibit exceptional ductility at warm-working temperatures and will be applicable to automotive and aerospace manufacturing operations.

Low-Cost Superplastic Ceramics

Sponsor: Texas Higher Education Coordinating Board

The recent discovery that very fine-grained ceramics can be superplastically formed at high temperatures has renewed interest in the use of ceramics in advanced applications such as heat engines. However, the extremely high cost of the ceramic powders that are needed to attain these fine grains size compared to conventional powders has contributed to high component cost and the resulting limited introduction of these materials. We propose to develop ceramic laminates that will dramatically reduce the raw materials costs needed to fabricate superplastic ceramics. This will be accomplished by using alternating layers of duplex (particulate) composites with different compositions. Duplex microstructures will allow the substitution of a large fraction of a relatively inexpensive powder for much high cost powders normally needed for superplastic forming. A simple demonstration shows that by fabricating duplex ceramics into laminates, a significantly greater fraction of low cost powder can be used while still retaining superplastic properties. We propose the development of an analytical model to predict the optimum ratio of layer thickness and volume fraction of low cost powder in the composite while still achieving superplasticity. The model will then be verified by fabricating and testing a duplex laminated composite made from a low cost alumina and superplastic yttria-stabilized zirconia.

Ultrahigh-Carbon Steels for Ultrahigh-Strength Wire Rope

Sponsors: Wire Rope Corporation of America and Schlumberger

The current technology for production of high-strength steel wire for high-performance wire rope typically utilizes steel materials of eutectoid or slightly less than eutectoid composition. By moving to ultrahigh-carbon steels, which contain greater than 1.1 weight percent carbon, tremendous strength gains are possible. Current research is focussed in smaller increases in carbon content, with gradual motion towards ultrahigh-carbon steel compositions that will produce a revolutionary category of wire rope products.

The Processing and Mechanical Behavior of Ultrahigh-Carbon Steels

Collaborators: Lawrence Livermore National Laboratory

The Taleff Research Group participates in several ongoing experimental investigations concerned with ultrahigh-carbon steels. These include investigations of processing for specialized microstructures and evaluation of the mechanical behaviors associated with these microstructures in various alloys. Items of particular interest are superplasticity, the development of pearlitic and spheroidized microstructures, creation of visible surface damasks, and the general mechanical properties of these materials, including strength, ductility, and fracture toughness.

Superplasticity in Metallic Alloys

Collaborator: Lawrence Livermore National Laboratory

The Taleff Research Group is involved in ongoing investigations concerned with various aspects of superplasticity and superplastic materials. Superplastic materials studied in the past and present include the following: magnesium-lithium alloys, ultrahigh-carbon steels, high-aluminum steel, aluminum alloys, and stainless steels. The superplastic behaviors of interest include: classical superplasticity, high-strain-rate superplasticity, solid-solution, and superplastic-like behavior.