scholarly journals Verification of a Commercial CALPHAD Database for Re and Ru Containing Nickel-Base Superalloys

2009 ◽  
Vol 289-292 ◽  
pp. 101-108 ◽  
Author(s):  
Ralf Rettig ◽  
Astrid Heckl ◽  
Steffen Neumeier ◽  
Florian Pyczak ◽  
Matthias Göken ◽  
...  
Keyword(s):  
High Temperature ◽  
Melting Point ◽  
Single Crystal ◽  
Weight Percent ◽  
Incipient Melting ◽  
High Temperature Properties ◽  
First Approximation ◽  
Nickel Base Superalloys ◽  
Nickel Base ◽  
Alloy Properties

The addition of rhenium and ruthenium to single crystal nickel-base superalloys improves the high-temperature properties of the alloys. In this work the applicability of the database TTNi7 (ThermoTech Ltd, UK) for developing 4th generation single crystal superalloys containing rhenium (Re) and ruthenium (Ru) was investigated. We systematically compared experimentally determined alloy properties to the predictions of ThermoCalc with the database TTNi7. The investigated properties were liquidus, solidus and ´ solvus temperature as well as incipient melting point and segregation. Calculations were based on thermodynamic principles with the assumption of either equilibrium or Scheil-Gulliver conditions, i.e. no diffusion in the solid and complete diffusion in the liquid. Furthermore the composition of the  and the  phase of a Re- and Ru-containing superalloy was measured and compared to calculations. Our results show that the database is capable of simulating general trends of 4th generation superalloys up to 6 weight percent (wt.-%) Re and 6 wt.-% Ru. The present work shows that Scheil-Gulliver calculations can only be used as a first approximation for nickel-base superalloys.

Modelling of High Temperature Oxidation of Alumina-Forming Single-Crystal Nickel-Base Superalloys

2012 ◽  
Vol 60 (15) ◽  
pp. 5468-5480 ◽  
Author(s):  
M. Bensch ◽  
A. Sato ◽  
N. Warnken ◽  
E. Affeldt ◽  
R.C. Reed ◽  
...  
Keyword(s):  
High Temperature ◽  
Single Crystal ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
Nickel Base Superalloys ◽  
Nickel Base

Nickel Base Superalloys Single Crystal Growth Technology for Large Size Buckets in Heavy Duty Gas Turbines

1991 ◽  
Author(s):  
Akira Yoshinari ◽  
Katsumi Iijima ◽  
Hideyo Kodama ◽  
Kimio Kano ◽  
Hiroyuki Matsuzaki
Keyword(s):  
Crystal Growth ◽  
High Temperature ◽  
Single Crystal ◽  
Gas Turbines ◽  
Single Crystal Growth ◽  
High Temperature Strength ◽  
Cross Sectional ◽  
High Temperature Mechanical Properties ◽  
Nickel Base Superalloys ◽  
Nickel Base

A larger size bucket with superior high temperature strength is required for future land based gas turbines. From the viewpoint of high temperature mechanical properties, single crystal alloys are rather promising. To grow larger sized single crystals of nickel base superalloys, a two stage heating and bypass process in which single crystal growth paths are incorporated into large cross sectional positions such as platforms has been developed. It results in successful single crystal growth of alloys for buckets with a total length of 170mm and large lateral cross section. Characteristics of single crystal buckets made by the bypass process and properties of an alumina mold prepared for a single crystal casting are described herein.

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