Dr. Lemberg specializes in failure analysis, fracture mechanics, metallurgy, and materials science engineering with an emphasis on understanding the fracture behavior of materials. He has expertise in mechanical testing, especially in the area of crack-growth resistance testing, as well as optical and electron microscopy, metallography, and fractography.
Prior to joining Exponent, Dr. Lemberg was a graduate research assistant at the University of California, Berkeley, where he studied the fracture behavior of Mo-Si-B alloys at ambient and ultra-high (1300°C) temperatures, the fracture behavior of carbon-nanotube-impregnated, Nb-toughened nanocrystalline alumina and the fracture behavior of alumina/silicon nitride functionally-graded joints at elevated temperatures. Dr. Lemberg also has experience studying the fatigue properties of tree-resistant cross-linked polyethylene insulation of underground power distribution cables.
Lemberg JA, Middlemas MR, Weingärtner T, Gludovatz B, Cochran JK, Ritchie RO. On the fracture toughness of fine-grained Mo-3Si-1B (wt.%) alloys at ambient to elevated (1300°C) temperatures. Intermetallics 2012; 20(1):141–154.
Lee CS, Lemberg JA, Cho DG, Roh JY, Ritchie, RO. Mechanical properties of Si3N4-Al2O3 FGM joints with 15 layers for high-temperature applications. Journal of the European Ceramic Society 2010; 30:1743–1749.
Thomson KE, Jiang D, Lemberg JA, Koester KJ, Ritchie, RO Mukherjee AK. In-situ bend testing of niobium-reinforced alumina nanocomposites with and without single-walled nanotubes. Materials Science and Engineering A 2008; 493:256–260.
Presentations
Lemberg JA, Middlemas MR, Cochran JK, Ritchie RO. Fracture behavior of Mo-Si-B alloys at elevated temperatures in air and inert atmospheres. TMS 2011 140th Annual Meeting and Exposition, San Diego, CA, 2011.
Lemberg JA, Ritchie RO. Fracture toughness of Mo-Si-B alloys at ambient and elevated temperatures. 12th International Conference on Fracture, Ottawa, Canada, 2009.