Ivica Smid
In searching for new methods of developing durable materials for tooling applications, Ivica ("Ivi") Smid, Associate Professor of Engineering Science and Mechanics, and others have developed a novel process called Tough Coated Hard Particles (TCHP). Traditional tools consist of a base material, chosen for its hardness, coated with a wear-resistant material. However, once the coating is removed, the tool is essentially useless; a costly proposition both in down-time and money. By combining hard coatings technology with sintering methods, Smid first coats hard refractory particles (such as TiN, Al2O3, or cubic BN) with tungsten carbide and cobalt and then forms tools by subjecting the coated particles to hot isostatic pressing.
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The resulting composite materials combine many desirable properties such as the toughness of tungsten carbide, the hardness/wear resistance of diamond, and the low density of titanium into a single part. Furthermore, these materials have extended lifetimes over conventional tool materials in that as the surface is worn, new wear-resistant material is available for use (see figures below). The limit of the usefulness is then only limited by the geometry of the device rather than the available coating.
TCHP is a promising alternative to traditional coating methods, however, some research and development is still necessary. Through further investigation into the combinations of materials used for TCHP and the fabrication process, Smid believes tools produced using TCHP should provide the highest combinations of toughness and hardness/wear resistance of all known materials.
Another exciting area of Smid's research focuses on the concept of Direct Rapid Prototyping (DRP). Traditionally, designers develop detailed CAD drawings of a part to be manufactured and from these drawings the part is machined from bulk stock or sintered from powdered materials. Direct Rapid Prototyping, and specifically direct laser sintering, provides a mechanism to turn detailed computer designed parts into a product in a matter of hours through a technique known as direct material build-up. The general principle of direct laser sintering is shown in the figure below.
Using a stage with 3-directional translation, a layered part is built by moving the stage horizontally while depositing liquid metal resulting from a metal powder stream being blown into a laser beam. Subsequent layers are produced by moving the stage vertically and depositing more metal. New layers in the part fuse into previous layers as new material is deposited. Smid's current research efforts in DRP focus on process development, specifically studying effects of particle size, feed rate, laser power and environmental conditions on the properties of the product.
After receiving his Ph.D. in physical chemistry from the University in Austria in 1987, Ivi Smid held various appointments in his native Austria, Japan and the United States. He came to Penn State in January 2002, joining the Engineering Science and Mechanics department and also working with the Center for Innovative Sintered Products (CISP).
