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Metallurgical and Materials Transactions A

, Volume 47, Issue 9, pp 4616–4624 | Cite as

Dilatometric Analysis and Microstructural Investigation of the Sintering Mechanisms of Blended Elemental Ti-6Al-4V Powders

Article

Abstract

The densification behavior of mixed Ti and Al/V master alloy powders for Ti-6Al-4V was investigated by a series of dilatometry tests to measure the shrinkage of the samples with the sintering temperature. The corresponding microstructural changes were examined under various sintering conditions with optical microscopy, energy-dispersive spectroscopy, and X-ray diffraction analyses. From these results, the consolidation of the mixed powders was divided into two domains: (i) sintering densification and solute homogenization of Ti and Al/V master alloy particles below 1293 K (1020 °C), and (ii) densification of Ti alloy phases above 1293 K (1020 °C). In the lower temperature region, the inter-diffusion between Ti and Al/V master alloy particles dominated the sintering of the mixed powders because the chemical gradient between two types of particles outweighed the surface energy reduction. Following chemical homogenization, the densification induced the shrinkage of the Ti alloy phases to reduce their surface energies. These tendencies are also supported by the density and grain size variations of the sintered specimens with temperature. The apparent activation energies of the sintering and grain growth for Ti alloy particles are 85.91 ± 6.93 and 37.33 kJ/mol, respectively, similar to or slightly lower than those of pure Ti particles. The difference was attributed to the slower self-diffusion of Ti resulting from the alloying of Al and V into in the Ti matrix.

Keywords

Sinter Temperature Master Alloy Mixed Powder Shrinkage Rate Sinter Densification 
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.

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Copyright information

© The Minerals, Metals & Materials Society and ASM International 2016

Authors and Affiliations

  1. 1.Department of Materials Science and EngineeringKorea Advanced Institute of Science and TechnologyDaejeonRepublic of Korea
  2. 2.Agency for Defense DevelopmentDaejeonRepublic of Korea
  3. 3.Department of Nuclear and Quantum EngineeringKorea Advanced Institute of Science and TechnologyDaejeonRepublic of Korea

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