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Mechanical Engineering

Mechanical Engineering

Materials Processing
Particulate Materials Science & Processing
graduate students working hard

 

The faculty conduct research and offer graduate courses (ME 543 Powder-Based Manufacturing, ME 596 Powder Injection Molding, ME 646 Mechanics of Sintering, and ME 696 Nanomaterials) on the fabrication science applied to discrete engineering components. Examples of discrete engineering components include oil well drilling tips made out of polycrystalline diamond, automotive hybrid electronics heat sinks made out of copper, low thermal expansion heat sinks made out of copper-tungsten, anti-armor projectiles made out of tungsten heavy alloys, neural and pressure sensors made out of titanium and nitinol respectively, and high performance rare earth magnets made out of FeNdB compositions. The fabrication of such components is largely associated with the many parameters and their interactions associated with taking the product from Powder Technology (powder, polymer, mixture of ingredients) and deciding on the compromise between cost and performance via the processing science - the compaction pressure, sintering time, sintering temperature, external pressure during pressing or sintering, heating rate, particle size, forming machine, sintering atmosphere, tool design, and means to measure properties. This fabrication process, in particular, and powder metallurgy, in general, competes as a technology with casting, machining, forging, and nowadays, additive manufacturing.

The goals are to rationalize new materials and applications to the body of knowledge on powder processing. New powder-based processing approaches that extend/enhance the current state of the art or open up new directions within powder processing science and technology are also being studied. What are very important science aspects are how to modify the surface wetting during liquid phase sintering to improve toughness, how to design the composite microstructure to maximize wear resistance while sustaining the lowest cost possible (and this includes the cost of component replacement), how to employ new polymers to modify the forming process such as in powder metal injection molding, and how to induce densification in sintering to attain maximum properties without loss of shape precision (that idea alone is a $10 billion issue for the cemented carbide industry).

The largest trend in powder metallurgy is global sourcing. Apple is the largest user of powder technology and all of their sintered components are sourced from China and Taiwan, Samsung from Korea, Motorola from Singapore and China, and even Google is relying on the technology for components using sources in Asia. Automotive production is largely relying on US based producers, but that is changing as one Taiwan company has opened a plant in Iowa (sales and demonstration in Iowa, production in Taiwan), as have German firms (Alabama, and Illinois), Spanish firms (Pennsylvania), Japanese firms (Indiana, North Carolina), and so on. Thus, the current research in this area is focused on the newer variants where there is still growth and employment and technical challenges in North America. A long-term plan is also to establish new processing approaches for adoption by the scientific and industrial communities.

Two former graduate students working in this area were employed by a company interested in tape casting for laminated tungsten-aluminum nitride heaters associated with microelectronics, one was hired by a manufacturer interested in porous sintered stainless steel, and one went to work in defense Research and Development. On the academic front, one recent Ph.D. recipient is now an Assistant Professor at another University teaching and doing research in the area of powder-based materials and processing 

Faculty:
Drs. German, Morsi, Olevsky 

Dept. of Mechanical Engineering, E-326

San Diego State University

5500 Campanile Drive

San Diego, CA 92182-1323