SBIR-STTR Award

DOE has identified a market need for a more economical, less energy intensive process for the production of high-quality, small diameter, feedstock without deleterious surface properties. Semi-solid metal forming involves the use of a special starting material (feedstock) that has been heated into a liquid + solid state. It provides a higher quality and more cost effective alternative to conventional means for forming parts close to their final shape. Currently commercial semi-solid forming is essentially confined to expensive electromagnetic stirring facilities that produce large diameter feedstock with deleterious surface properties. The objective of this project is to develop an economical mechanical stirring process for the production of small diameter semi-solid forming feedstock free of deleterious surface structures. The Phase I project will develop a small scale mechanical stirring facility and demonstrate the feasibility for production of the desired feedstock. The feedstock as well as simple formed parts will be evaluated. In Phase II, the facility developed in Phase I will be scaled up and detailed processing procedures developed to bring the process to the point of commercialization.

Commercial Applications and Other Benefits as described by the awardee:
If the research effort is successful, this technology will directly benefit industries that require the production of relatively small parts to near final shape. The aerospace, automotive and computer hardware industries will benefit directly from this technology. Furthermore, scale-up to larger diameter feedstock would potentially impact the entire light alloy, near net shape forming industry.

The DOE has identified a market need for the economical formation of special starting material (feedstock) with appropriate microstructure across an entire small diameter cross-section. This project will develop a commercially-viable process for producing such aluminum alloy feedstock using a semisolid metal forming process with mechanical stirring. In Phase I, the feasibility of producing mechanically stirred feedstock with appropriate microstructure and rheological data acquisition was demonstrated. A mechanically stirred batch rheocaster was developed with digital temperature, shear rate, and torque data acquisition. Rheology data on aluminum alloy 357 was acquired to establish the adequacy of the rheology data acquisition system. The feedstock=s microstructure was assessed by light microscopy, and techniques for quantitative stereological characterization were developed. In Phase II a continuous, mechanically stirred feedstock casting process will be developed in which microstructural control is correlated with rheological control. A larger throughput, mechanically stirred continuous caster will be developed to produce small diameter aluminum alloy feedstock. A more sophisticated system for rheological control will be developed and correlated with microstructural control via extensive metallographic and stereological analysis of microstructure.

Commercial Applications and Other Benefits as described by the awardee:
A more economical, commercial means for producing fine grained, small diameter feedstock for semisolid metal forming should also provide a more cost effective route to the production of larger diameter, microstructurally uniform feedstock than currently available.