Grain Growth in Dilute Tungsten Heavy Alloys during Liquid-Phase Sintering under Microgravity Conditions

  • John L. JohnsonEmail author
  • Louis G. Campbell
  • Seong Jin Park
  • Randall M. German


Tungsten heavy alloys with compositions ranging from 35 to 93 wt pct tungsten were liquid-phase sintered at 1500 °C under microgravity conditions for isothermal hold times ranging from 1 to 600 minutes. The solid-volume fraction, grain size, grain size distribution, connectivity, and contiguity of the sintered microstructures were quantitatively measured. From these data, grain-growth-rate constants are determined for solid-volume fractions ranging from 0.048 to 0.858 and are compared to the predictions of several grain-coarsening models. The measured grain size distributions are shown to be self-similar and are fit to a Weibull distribution. Three-dimensional (3-D) grain size distributions from several coarsening models are transformed into grain size distributions for two-dimensional (2-D) cross sections, for comparison with the experimental data. Chi-squared tests and G-tests show that a coalescence model for grain growth fits the experimental observations better than solution-reprecipitation models, even for dilute tungsten heavy alloys.


Grain Size Distribution Weibull Distribution Microgravity Condition Rayleigh Distribution Tungsten Heavy Alloy 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This research was supported by the U.S. National Aeronautics and Space Administration under continuing grants from 1985 to 2006.


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Copyright information

© The Minerals, Metals & Materials Society and ASM International 2009

Authors and Affiliations

  • John L. Johnson
    • 1
    Email author
  • Louis G. Campbell
    • 2
  • Seong Jin Park
    • 3
  • Randall M. German
    • 4
  1. 1.ATI Engineered ProductsHuntsvilleUSA
  2. 2.Eaton Corporation, VI TechnologyHorseheadsUSA
  3. 3.Center for Advanced Vehicular SystemsMississippi State UniversityStarkvilleUSA
  4. 4.College of EngineeringSan Diego State UniversitySan DiegoUSA

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