Dr. Suryanarayana’s research is centered on advanced materials including high-temperature intermetallics, nanostructured materials, bulk metallic glasses, thin films and coatings. The processing of these materials is done under non-equilibrium conditions by methods such as rapid solidification processing, mechanical alloying, and physical vapor deposition, and characterization is done by techniques such as microscopy, diffraction, and calorimetry. Nanocrystalline materials have a large volume fraction of atoms in the grain boundaries and consequently, they exhibit vastly improved properties. His research interests in this area include processing of nanocrystalline materials by mechanical alloying methods, optimization of processing conditions, investigating methods of consolidating them to full density, and evaluating the thermal stability of the microstructure. He has shown that it is possible to consolidate nanocrystalline powders at temperatures much lower than those required for coarse-grained materials, and that, by properly choosing the conditions, it is possible to retain nanocrystalline grain structures after consolidation.

Work is currently in progress to consolidate mechanically alloyed MoSi2 powders to full density. Sputtering Targets for the electronic industry can be prepared easily or with great difficulty depending upon the number of components involved in the target. He has developed a novel powder metallurgy technique to produce Cu-In-Ga-Se targets by mechanically alloying the blended elemental powders in a ball mill and hot isostatically pressing the powder into the target. It was possible to economically achieve the target of the desired stoichiometry by milling the blended elemental powder for 2 hours and pressing it at 750 oC and 100 MPa pressure for 2 hours. This type of approach can be easily extended to the fabrication of other targets as well. Bulk metallic glasses can be produced by solidification methods in selected alloy systems which are amenable to glass formation at low cooling rates. But, processing of bulk metallic glasses of sufficient thickness has not been possible. Dr. Suryanarayana is developing novel compositions of iron-based bulk metallic glasses using alternate methods. Blended elemental mixtures of suitable powder mixtures will be produced in a glassy condition by mechanical alloying. These powders will then be consolidated to full density of any size and shape by innovative methods such as HIPing or shock consolidation methods.

Selected Publications

C. Suryanarayana, Non-equilibrium Processing of Ultrafine Grained Titanium Aluminides, International Journal of Non-equilibrium Processing, 11 (2002) 325-345.

C. Suryanarayana, Mechanical Alloying and Milling, Progress in Materials Science, 46 (2001) 1-184.

C. Suryanarayana and C.C. Koch, Nanocrystalline Materials – Current Research and Future Directions, Hyperfine Interactions, 130 (2000) 5-44.

C. Suryanarayana, S.H. Yoo and J.R. Groza, Consolidation of Mechanically Alloyed Cu-In-Ga-Se Powders, Journal of Materials Science Letters, 20 (2001) 2179-2181.

S.J. Hong, T.S. Kim, C. Suryanarayana and B.S. Chun, Mechanical Milling of Gas-Atomized Al-Ni-Mm (Mm = Misch Metal) Alloy Powders, Metallurgical and Materials Transactions A, 32A (2001) 821-829.

Advantage of Mechanical Alloying of Blended Elemental Powders
in Achieving and Retaining Nanostructures