Effects of Impurity Elements on Green Strength of Powder Compacts

Abstract:

The green strength of a powder compact results from the mechanical interlocking of the irregularities on the particle surfaces. During compaction, particle rearrangement, plastic deformation and particularly surface deformation of powders occur. Titanium powder is susceptible to interstitial element contamination, which may lead to solid solution strengthening of the particles and/or the formation of non-metallic compounds on the surface. However, the influence of these various impurities, namely oxygen and nitrogen, on the green strength has not been investigated. This work investigates and quantitatively evaluates the factors influencing the green strength of the powder compacts. The indirect tensile test was applied for the determination of the green strength of the powder compacts, and test results were compared to that of a more conventional 3-point bending test. The substantial dependence of green strength on both the amount of impurity element in the core of the powder particles and the compaction pressure is demonstrated. The effect of the surface condition of the powder particles on green strength is also reported.

• Periodical: Materials Science Forum (Volumes 654-656)
• Pages: 811-814
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.654-656.811
• Online since: June 2010
• Authors: Ju Beom Lim, Colleen J. Bettles, Barry C. Muddle, Nho Kwang Park
• Keywords: Green Strength, Nitrogen Content, Oxygen Content, Titanium Powder Compact

References

[1] H. Conrad: Progress Materials Science Vol. 26 (1981), pp.123-403.

[2] ASTM B312-09 Standard test method for green strength of specimens compacted from metal powders.

[3] G. O'Donnell and L. Looney: Key Engineering Matrials Vols. 127-131 (1997) pp.479-486.

[4] A. Laptev, O. Vyal, M. Bram, H.P. Buchkremer and D. Stover: Powder Metallurgy, Vol. 48(4) (2005), pp.358-364.

DOI: 10.1179/174329005x73838

[5] N. Claussen and J. Jahn: Powder Met. Inter. Vol. 2(3) (1970), pp.87-90.

[6] H. Rode and V. Hlavacek: Combustion Science and Technology, Vol. 99(1) (1994), pp.161-177.

[7] H. Rode and V. Hlavacek: Combustion Science and Technology, Vol. 99(1) (1994), pp.143-160. (c) (b) (a).