Pressureless Sintering of Mo-Si-B Alloys with Fe Additive
- 136 Downloads
The sintering behavior of Mo-Si-B alloys with iron as a sintering additive was investigated. The addition of small amounts of Fe effectively enhanced the densification of Mo-Si-B at temperatures below 1900 °C. The addition of 5 at.% Fe resulted in nearly full densification (97.0% of theoretical density) when sintered at 1750 °C for 2 h, while the unmodified Mo-Si-B alloy could be densified to only 66.8% of its theoretical density under these conditions. Addition of 0.5 at.% Fe and 2 at.% Fe increased the degree of densification of Mo-Si-B by 15.4 and 17.0%, respectively, and led to nearly full densification at 1900 and 1850 °C, respectively. Fe-Si-B eutectic liquid was formed at low temperatures and disappeared at high temperatures. We propose that the addition of Fe led to the formation of a transient liquid, facilitating liquid-phase sintering of the powder compacts.
KeywordsEDS intermetallics liquid-phase sintering Mo-Si-B pressureless sintering SEM transition metal silicides ternary silicide borides XRD
This work was supported by the AFOSR HTAM under contract #FA9550-11-1-201. The authors would like to thank Warren Straszheim for his help in the WDS analyses.
- 21.I. Tomaszkiewicz, G.A. Hope, C.M. Beck Ii, and P.A.G. O’Hare, Thermodynamic Properties of Silicides V. Fluorine-Combustion Calorimetric Determination of the Standard Molar Enthalpy of Formation at the Temperature 298.15 K of Trimolybdenum Monosilicide Mo3Si, and a Critical Assessment of its Thermodynamic Properties, J. Chem. Thermodyn., 1996, 28(1), p 29–42CrossRefGoogle Scholar
- 29.N.F. Chaban and Y.B. Kuz’ma, Phase Equilibria in the Systems Manganese-Silicon-Boron and Iron-Silicon-Boron, Inorg. Mater., 1990, 6, p 883–884Google Scholar