During metal injection moulding (MIM) processing, titanium tends to react with carbon from the polymeric binder. Thus, carbides, which can effect embrittlement, might be formed if the carbon solubility of the alloy is exceeded. Especially in β-titanium alloys, this is a critical issue, because β-phase stabilising elements like V, Mo and Nb decrease the carbon solubility of the Ti-matrix. This study summarises studies with different approaches to limit carbide precipitation in a Ti–22wt-%Nb alloy processed by MIM. Adding Zr led to a significant reduction in the amount and size of carbides due to an increase in the lattice constant. Furthermore, boron was added supporting a finer distribution of the carbides. Scanning electron microscopy and transmission electron microscopy investigations reveal the role of the elemental additions and analyse the structure of the different carbides formed. Combinations with heat treatments led to significant reduction in the amount of carbides.
GermanR.Progress in titanium metal powder injection moulding. Materials. 2013;6:3641–3662. doi: 10.3390/ma6083641
2.
EbelT, FriedericiV, ImgrundP, Metal injection moulding of titanium. In: QianM, FroesFH, editors. Titanium powder metallurgy. Butterworth-Heinemann; 2015. p. 337–360(ISBN: 978-0-12-800054-0).
3.
AustE, LimbergW, GerlingR, Advanced TiAl6Nb7 bone screw implant fabricated by metal injection moulding. Adv Eng Mater.2006;8(5):365–370. doi: 10.1002/adem.200500134
4.
OsadaT, MiuraH, ItohY, Optimization of MIM process for Ti-6Al-7Nb alloy powder. J Jpn Soc Powder Powder Metall.2008;55:726–731. doi: 10.2497/jjspm.55.726
5.
LimbergW, EbelT, PyczakF, Influence of the sintering atmosphere on the tensile properties of MIM processed Ti 45Al 5Nb 0.2B 0.2C. Mat Sci Eng A. 2012;552:323–329. doi: 10.1016/j.msea.2012.05.047
6.
MiuraH, KangH, ItohY.High performance titanium alloy compacts by advanced powder processing techniques. Key Eng Mat.2012;520:30–40. doi: 10.4028/www.scientific.net/KEM.520.30
7.
EbelT, FerriOM.Processing of Ti-15V-3Al-3Sn-3Cr by metal injection moulding. Proceedings of EuroPM 2011, Vol. 2; 2011 Oct 9–12; Barcelona, Spain. p. 265–270.
8.
BidauxJ-E, ClosuitC, Rodriguez-ArbaizarM, Metal injection moulding of Ti–Nb alloys for implant application. Eur Cells Mater.2011;22:32.
9.
ZhangH, HeX, QuX, Microstructure and mechanical properties of high Nb containing TiAl alloy parts fabricated by metal injection molding. Mat Sci Eng A. 2009;526:31–37. doi: 10.1016/j.msea.2009.07.003
10.
XiaY, SchafferGB, QianM.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. J Alloys Compd. 2013;578:195–201. doi: 10.1016/j.jallcom.2013.05.104
11.
TakekawaJ, SakuraiN.Effect of processing conditions on density, strength and microstructure of Ti-12Mo alloy fabricated by PIM process. J Jpn Soc Powder Powder Metall.1999;46:877–881. doi: 10.2497/jjspm.46.877
12.
BarilE, LefebvreLP, ThomasY.Interstitial elements in titanium powder metallurgy: sources and control. Powder Metall.2011;54(3):183–186. doi: 10.1179/174329011X13045076771759
13.
YanM, DarguschMS, EbelT, A transmission electron microscopy and three dimensional atom probe study of the oxygen-induced fine microstructural features in as sintered Ti-6Al-4V and their impacts on ductility. Acta Mater. 2014;68:196–206. doi: 10.1016/j.actamat.2014.01.015
14.
EbelT, FerriOM, LimbergW, Metal injection moulding of titanium and titanium-aluminides. Key Eng Mat.2012;520:153–160. doi: 10.4028/www.scientific.net/KEM.520.153
15.
YanWXM.Review of effect of oxygen on room temperature ductility of titanium and titanium alloys. Powder Metall. 2014;57(4):251–257. doi: 10.1179/1743290114Y.0000000108
16.
YanM, QianM, KongC, Impacts of trace carbon on the microstructure of as-sintered biomedical Ti–15Mo alloy and reassessment of the maximum carbon limit. Acta Biomater. 2014;10(2):1014–1023. doi: 10.1016/j.actbio.2013.10.034
17.
ZhaoD, ChangK, EbelT, Microstructure and mechanical behavior of metal injection molded Ti–Nb binary alloys as biomedical material. J Mech Behav Biomed Mater.2013;28:171–182. doi: 10.1016/j.jmbbm.2013.08.013
18.
ZhaoD, EbelT, YanM, Trace carbon in biomedical β-titanium alloys: recent progress. J Metall. 2015;67(10):2236–2243.
19.
ShatynskiSR.The thermochemistry of transition metal carbides. Oxid Met. 1979;13(2):105–118. doi: 10.1007/BF00611975
20.
FerriOM, EbelT, BormannR.High cycle fatigue behaviour of Ti–6Al–4V fabricated by metal injection moulding technology. Mater Sci Eng A. 2009;504(1–2):107–113. doi: 10.1016/j.msea.2008.10.039
SantosPF, NiinomiM, LiuHH, Fabrication of low-cost β-typeTi–Mn alloys for biomedical applications by metal injection molding process and their mechanical properties. J Mech Behav Biomed Mater.2016;59:497–507. doi: 10.1016/j.jmbbm.2016.02.035
23.
ChoK, NiinomiM, NakaiM, Improvement in mechanical strength of low-cost β-type Ti-Mn alloys fabricated by metal injection molding through cold rolling. J Alloys Compd. 2016;664:272–283. doi: 10.1016/j.jallcom.2015.12.200
