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Computer simulations of microstructures and properties. Both theoretical and empirical approaches are being made mainly with Ni-base superalloys and Ir-base refractory superalloys.
(1) Statistical Thermodynamics
Cluster Variation and Monte Carlo simulations for multi-
component superalloys containing Re, Ir, etc.
(2)Thermodynamics
An equilibrium calculation model for multi-component Ni-base
superalloys, containing platinum group metals, etc.
(3)Empirical approach
Databese and regression analysis: Alloy Design Program.
etc.
Microstructure evolution during process and service is being analised on different scales by using some equipments.
(1)APFIM
Phase equilibrium, site occupation, composition profile at
phase interface, etc.in multi-component Ni-base superalloys.
(2)TEM
A TEM equipped with high temperature tensile holder is to be
installed for in-situ observations of microstructure
evolution and dislocation motion during creep.
(3)High Temp. X-ray Diffractometry
An X-ray Diffractometer with a hot stage (up to 1200C) is being
used for misfit and lattice distortion measurements in
coherent structures.
(4)Elastic moduli measurement
Elastic moduli measurement is being made with a new equipment
up to 1100C.
(5)Creep analysis
Creep behaviour of SC/DS superalloys, e.g., 3rd generation
alloys,is being analysed in connection with the micro-
structural parameters above.
etc.
Single crystal (SC) and directionally solidified (DS) superalloys are being developed under collaborations with private companies.
(1)Large gas turbines for combined cycle power plants Development of new SC superalloys and its application to actual gas turbines. An NRIM 3 rd generation SC superalloy (TMS-75) and a newly developed SC superalloy (TMS-82)are going to be tested in a gas turbine in 2000 year.
(2)Small gas turbines for co-generations, etc.
Development of new SC/DS superalloys with higher temperature
capabilities as well as better hot corrosion resistance is
conducted.
(3)Jet engines
Development of 4th genaration superalloys is being carried
out.
etc.
Si3N4 with controlled grain boundary is being investigated. A Yb addition with some other ceramics to crystalise the glass phase is successfully applied.
Ultra-high temperature alloys with fcc/L12 coherent structures are being developed.
(1)Ir/Rh-base refractory superalloys
Ir/Rh-X (X= Nb,Hf,Zr, etc) binary alloys. Effects of L12
volume fraction, lattice misfit, morphology, etc on
mechanical properties, deformation mechanisms, etc.
(2)Ductilisation of the refractory superalloys
Additions of minor elements including B, C, etc. as well as
major additions of Ni etc.for ductilisation.
(3)Mixing Ir-base and Ni-base superalloys
Balancing cost performance, specific weight, etc is being
tried by mixing the two superalloys in a different fractions.
etc.
A virtual gas turbine system is being constructed in a computer by combining CFD, heat transfer analysis, and stress analysis programs with materials simulation programs.
Project Director: Hiroshi Harada (HARADA.Hiroshi@nims.go.jp)