Alumix 431D pre-alloyed powder (ECKA Granules GmbH) containing 1.5 mass% of Acrawax C was used to study the effect of nitrogen flow rate on delubrication and sintering evolution. Mass loss of compacts during heating was controlled by the TG method using a STA Netzsch apparatus coupled with a mass spectrometer. The latter was used to identify the volatile lubricant's decomposition products. Macro- and microstructural observations of sintered compacts were also performed. The results documented a strong influence of nitrogen flow rate on delubrication and thus on the sintering behaviour of examined powder. High nitrogen flow rate is required to produce the desired sintered compacts. In contrast, at low nitrogen velocity, the lubricant removal is not complete, which leads to the formation of carbonaceous residuals in the form of soot, which in turn significantly impedes densification and deteriorates the sintered products.
Lonza Inc. Leaflet “ACRAWAX C”, 2010, www.lonza.com, assessed in II.2017
2.
SahaD, ApelianD.Optimization of de-lubrication during sintering, Proceedings of the International Conference on Powder Metallurgy and Particulate Materials; New York: MPIF; 2000. Vol. 5, p. 183–190
3.
SahaD, BaumMM, ApelianD.Mechanism of de-lubrication during sintering: reaction kinetics and decomposition stages. Proceedings of the International Conference on Powder Metallurgy and Particulate Materials; New Orleans: MPIF; 2001, Vol. 5. p. 82–94.
4.
SahaD, ApelianD.Control strategy for the de-lubrication of P/M compacts. Int J Powder Metall. 2002;38(3):71–79.
5.
PoskrebyshevGA, BaumMM, MossJA, . Catalytic effect of Fe/C powder on the formation of gas-phase products of vacuum pyrolysis of N,N-ethylene bisstearamide,. Appl Catal A: Gen. 2007;327:52–65. doi: 10.1016/j.apcata.2007.04.026
6.
North American Höganäs, leaflet “Intralube E”, 2009.
7.
LefebvreL-P, ThomasY.New admixed lubricant for press and sinter aluminium powder metallurgy applications. Proceedings of the International Conference on P/M Aluminium and Light Alloys for Automotive Applications, Detroit, 1998. p. 51–58.
8.
LefebvreL-P, ThomasY.Lubricating aluminium powder with polyethylene for press and sinter PM applications. Int J Powder Metall. 1999;35(5):45–53.
9.
WimbertL, DollmeierK, KruzhanovV, . Advanced lubricants – a complex challenge for powder metallurgy: density, lubricity, environment, Proceedings of the PM World Congress, Florence, EPMA, Shrewsbury, Vol. 1, 2010. p. 549–556.
10.
OhMC, SeokH, KimH-J, . De-lubrication behaviour of novel EBS based admixed lubricant in aluminium alloy. Arch Metall Mater. 2015;60(2):1427–1431.
11.
Ecka Granules – Metal Powder Technologies. ECKA ALUMIX® 431. Brochure: Press-Ready Mix for Aluminum Sintered Parts; 2010.
12.
DanningerH, NeubingHC, GradlJ.Sintering of high strength Al–Zn–Mg–Cu alloys to controlled dimension. Proc. PM World Congress Granada, 1998. p. 272–277.
13.
GradlJ, NeubingHC, MüllerA.Improvement in the sinterablility of 7-xxx based Aluminium Premix, 2004, Proc. PM World Congress, Wien, vol. 4, 15–21.
14.
MühlburgerM, PaschenP.Flüssigphasensintern von AlZnMgCu – Legierungen. Zeitschrift für Metalkunde. 1993;84(5):346–350.
15.
SchafferGB, HuoSH.On development of sintered 7xxx series aluminum alloys. Powder Metall. 1999;42:219–226. doi: 10.1179/003258999665558
16.
MartinJM, CastroF.Alloy development and associated dimensional changes of aluminium alloys during liquid phase sintering. Mater Sci Forum. 2003;426–432:107–114. doi: 10.4028/www.scientific.net/MSF.426-432.107
17.
MartinJM, CastroF.Liquid phase sintering of P/M aluminium alloys: effect of processing conditions. J Mater Process Technol. 2003;143–144(1–3):814–821. doi: 10.1016/S0924-0136(03)00335-2
18.
PieczonkaT, KaziorJ, Szewczyk-NykielA, . The effect of the atmosphere on sintering of Alumix 431D powder. Powder Metall. 2012;55:354–360. doi: 10.1179/1743290112Y.0000000015
19.
LaDelphaADP, NeubingH, BishopDP.Metallurgical assessment of an emerging Al-Zn-Mg-Cu P/M alloy. Mater Sci Eng, A. 2009;520:105–113. doi: 10.1016/j.msea.2009.05.039
20.
NeubingHC.Sinteraluminium – Der konsequente Weg vom Pulverprodukt zum Leichtbauteil, 2004, Hagen Symposium, 3-29.
21.
MassalskiTB.Binary alloys phase diagrams. Metals Park (OH): ASM; 1990.
22.
MartinJM, NavarcorenaB, ArribasI, . Dimensional Changes and Secondary Porosity in Liquid Phase Sintered Al Alloys, 2004, Proc. EURO PM2004, vol.4, pp. 46–53.
23.
QuadbeckP., SchreyerB., StraußA, . In-situ monitoring of gas atmospheres during debinding and sintering of PM steel components, Proceedings of the PM World Congress, Florence, EPMA, Shrewsbury, 2010, Vol. 2, p. 239–245.
24.
TaleghaniMAJ, NavasEMR, TorralbaJM.Microstructural and mechanical characterisation of 7075 aluminium alloy consolidated from a premixed powder by cold compaction and hot extrusion. Mater Des. 2014;55:674–682. doi: 10.1016/j.matdes.2013.10.028
25.
QuadbeckP, StraußA, MüllerS, . Atmosphere monitoring in a continuous sintering belt furnace. J Mater Process Technol. 2016;231:406–411. doi: 10.1016/j.jmatprotec.2016.01.015
26.
NeubingHC, DanningerH.Neuere Entwicklungen bei Al-Basis-Sintermischungen für Präzisionsteile. Pulvermetallurgie in Wissenschaft und Praxis. 1998;14:266–287.
