Accession Number : ADA489975


Title :   Gamma Prime Morphology and Creep Properties of Nickel Based Superalloys With Platinum Group Metal Additions (Preprint)


Descriptive Note : Conference proceedings


Corporate Author : MICHIGAN UNIV ANN ARBOR DEPT OF MATERIALS SCIENCE AND ENGINEERING


Personal Author(s) : Sluytman, J. S. ; Suzuki, A. ; Bolcavage, A. ; Helmink, R. C. ; Ballard, D. L. ; Pollock, T. M.


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA489975


Report Date : APR 2008


Pagination or Media Count : 12


Abstract : The microstructure and creep properties of platinum group metal (PGM) modified nickel based superalloys have been investigated. Alloys containing Pt and/or Ir along with variations in Cr, Ta, Re, Ru, and W exhibited relatively high solidus and liquidus temperatures. Differential thermal analysis (DTA) showed a strong dependence of the gamma' solvus on the level of Ta. The morphology of the gamma' precipitates was influenced by the presence of Cr, Ta, Ru, and W and ranged from cuboidal to semi-spherical. Compression creep tests were conducted at 1000 C at stresses ranging from 40 to 90 MPa. Alloys containing approximately 8 wt% Pt combined with Cr and Ta displayed the best resistance to creep deformation at stresses around 80 MPa. Post-creep analysis of the rafted structures indicated that all PGM modified alloys without Ru and W possessed positive misfit with magnitudes ranging from ~0.3 to 1.5%. The partitioning of PGMs between the gamma and gamma' phases and their resultant influence on creep performance is discussed.


Descriptors :   *CREEP , *SUPERALLOYS , *NICKEL ALLOYS , *PLATINUM , DIFFERENTIAL THERMAL ANALYSIS , PRECIPITATES , LIQUID PHASES , DEFORMATION , MICROSTRUCTURE , METALS , GAMMA RAYS


Subject Categories : PROPERTIES OF METALS AND ALLOYS


Distribution Statement : APPROVED FOR PUBLIC RELEASE