PIM Structures: Addition of Rare Earth Elements to MIM-Processed TiAl6V4

For medical implants as well as for engineering application, the fatigue resistance of titanium alloys is as important as the quasi-static mechanical properties. In order to improve both, a fine microstructure is necessary. One way to achieve this is the pinning of the grain-boundaries by adding fin...

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Bibliographic Details
Published inEuropean Congress and Exhibition on Powder Metallurgy. European PM Conference Proceedings p. 1
Main Authors Limberg, W, Ebel, T, Kainer, K U
Format Conference Proceeding
LanguageEnglish
Published Shrewsbury The European Powder Metallurgy Association 01.01.2014
Subjects
Colonies & territories
Earth
Light
Metal fatigue
Microstructure
Porosity
Raw materials
Scanning electron microscopy
Sintering
Studies
Titanium alloys
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Summary:For medical implants as well as for engineering application, the fatigue resistance of titanium alloys is as important as the quasi-static mechanical properties. In order to improve both, a fine microstructure is necessary. One way to achieve this is the pinning of the grain-boundaries by adding fine stable particles in order to hinder grain growth during sintering. In this study tensile test specimens were produced by MIM using gas atomised TiAl6V4-powder with additions of different oxide particles (MgO, CeO^sub 2^, ZrO^sub 2^, Y^sub 2^O^sub 3^ and CaO,) as well as pure TiAl6V4-powder as reference. The used oxide powder particles were of spherical shape and particle sizes were in a range from 200 to 600 nm. The specimens were sintered at 1350 °C for two hours. The addition of fine oxide particles led to a refinement of microstructure in every case. The strongest effect was found for the addition of calcium oxide which reduces the colony size to 50 percent compared to the reference without oxide addition. Furthermore, the addition of sub-micron oxide particles only led to a slight increase of the porosities of the sintered parts. Only the addition of fine yttrium oxide (Y^sub 2^O^sub 3^) particles led to a remarkable increase of porosity. It strongly hindered the densification during sintering and generated a fine grained highly porous microstructure with a density of less than 3.9 g/cm^sup 3^.