The effect of a small addition of nickel on the sintering, sintered microstructure, and mechanical properties of Ti-45Al-5Nb-0.2C-0.2B alloy

Xia, Y., Schaffer, G. B. and Qian, M. (2013) The effect of a small addition of nickel on the sintering, sintered microstructure, and mechanical properties of Ti-45Al-5Nb-0.2C-0.2B alloy. Journal of Alloys and Compounds, 578 195-201. doi:10.1016/j.jallcom.2013.05.104


Author Xia, Y.
Schaffer, G. B.
Qian, M.
Title The effect of a small addition of nickel on the sintering, sintered microstructure, and mechanical properties of Ti-45Al-5Nb-0.2C-0.2B alloy
Journal name Journal of Alloys and Compounds   Check publisher's open access policy
ISSN 0925-8388
1873-4669
Publication date 2013-11-01
Year available 2013
Sub-type Article (original research)
DOI 10.1016/j.jallcom.2013.05.104
Volume 578
Start page 195
End page 201
Total pages 7
Place of publication Amsterdam, The Netherlands
Publisher Elsevier BV
Collection year 2014
Language eng
Formatted abstract
Titanium aluminide based pre-alloyed powder is difficult to consolidate by pressureless sintering. The effect of a small addition of nickel (Ni) on the sintering, sintered microstructure, and mechanical properties of a Ti-45Al-5Nb-0.2C-0.2B alloy, compacted from pre-alloyed powder, has been investigated. The relative density of the alloy, sintered at 1375 °C for 60 min, increased progressively from 74% to >99% with increasing Ni content from 0% to 1.25 at.%. The addition of Ni leads to the formation of an intermediate hexagonal-structured Al3NiTi2 phase (known as the τ3 phase) during heating prior to reaching 1150 °C. The presence of the τ3 phase enables the formation of a Ni-containing sintering liquid through three reactions between 1250 °C and 1350 °C: τ3 + γ → Liquid, τ3 + γ → Liquid + α and τ3 + α → Liquid. The sintering shrinkage of the powder blend Ti-45Al-5Nb-0.2C-0.2B-1.25Ni occurs mostly before reaching the isothermal sintering temperature (1375 °C). Consequently, the sintered density increases only marginally during the subsequent isothermal sintering at 1375 °C from 15 min to 60 min and remains unchanged afterwards. However, achieving a near full lamellar structure requires a longer isothermal hold (120 min) at the single α phase region. The as-sintered Ti-45Al-5Nb-0.2C-0.2B-l.25Ni alloy shows compression strength of 2200 ± 50 MPa, yield strength of 750 ±20 MPa, and strain to fracture of 28 ±0.5%.
Keyword Titanium aluminide
Nickel
Sintering
Densification
GammaTitanium Aluminide
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mechanical & Mining Engineering Publications
Official 2014 Collection
 
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