Date: Thursday, Apr 28th
Presenter: Matthew Kramer, Senior Scientist, Ames Laboratory, and Professor, Materials Science and Engineering, Iowa State University
Using a series of computational methodologies ranging from semi-empirical methodologies to more accurate ab initio methods we have identified the Mo-Ni-Al system as a potential base alloy for high temperature applications. Of the a refractory metals, Mo appears to be the best candidate for combining a skeleton of a creep resistant metal with a high temperature intermetallic as a source of the oxidatively stable elements. Initial oxidation tests at 1150°C and above, while promising, shows that additional Platinum group metals (X) are required to boost oxidation stability above 1300°C. Key to maintaining fracture toughness, creep strength and a prime-reliant oxidation protection will be synthesis methods to assemble the refractory metal and the oxidatively protective phases at the appropriate length scales. I will also discuss a computational approach to optimize the Mo grain size and distribution in order to maximize the Mo fraction in the alloy without compromising oxidation stability.