Liquid phase sintering (LPS) of powder metallurgy (PM) components is a well-recognised strategy to enhance the densification of pressed-and-sintered compacts. This work reports the investigation on the liquid phase formation when a Fe–Ni–Mn–C–B master alloy (MA) is used as a boron carrier in combination with two iron base powders pre-alloyed with Mo. Through differential scanning calorimetry tests, quantitation of the microstructure with the help of artificial intelligence, as well as measurement of sintered density and strength as a function of sintering temperature, it was possible to unravel the mechanisms that take place before and during LPS. It was confirmed that a cascade of events takes place in the solid state prior to reaching the temperature necessary for a eutectic reaction to form a liquid. Additionally, the pre-alloyed Mo content was identified as a factor that modifies the initiation of LPS but not the LPS mechanisms per se.
SalakA.Ferrous powder metallurgy. RiecanskyV, editor. Cambridge: Cambridge International Science; 1995.
2.
OroR, CamposM, Gierl-MayerC, . New alloying systems for sintered steels: critical aspects of sintering behavior. Metall Mater Trans A. 2015;46(3):1349–1359.
3.
HryhaE, DudrovaE, NyborgL.Critical aspects of alloying of sintered steels with manganese. Metall Mater Trans A. 2010;41(11):2880–2897.
4.
SainzS, VeigaA, CastroFR.Sintered Mn-containing steels for high-performance applications. Int J Powder Metall. 2016;52(2):47–55.
5.
GermanRM, SuriP, ParkSJ.Review: liquid phase sintering. J Mater Sci. 2009;44(1):1–39.
6.
LiuJ, CardamoneA, PotterT, . Liquid phase sintering of iron–carbon alloys with boron additions. Powder Metall. 2000;43(1):57–61.
7.
XiuZ, SalwénA, QinX, . Sintering behaviour of iron-molybdenum steels with the addition of Fe-B-C master alloy powders. Powder Metall. 2003;46(2):171–174.
8.
WuM-W.The influences of carbon and molybdenum on the progress of liquid phase sintering and the microstructure of boron-containing powder metallurgy steel. Metall Mater Trans A. 2015;46(1):467–475.
9.
DanningerH, VassilevaV, Gierl-MayerC.Embrittling components in sintered steels: comparison of phosphorus and boron. Powder Metall Prog. 2017;17(1):47–64.
10.
SundaramMV, SurreddiKB, HryhaE, . Enhanced densification of PM steels by liquid phase sintering with boron-containing master alloy. Metall Mater Trans A. 2018;49(1):255–263.
11.
Gierl-MayerC, ZbiralJ, DanningerH. Enhanced sintering of PM steels by addition of Fe-Ni-B masteralloy. Euro PM2014; 2014 Sep 21–24; Salzburg, Austria. EPMA; 2014.
12.
VeigaA, BilbaoC, SainzS, . Controlled shrinkage of low alloy PM steels during LPS. In: BingertSR, LukSH, editors. International Conference on Powder Metallurgy & Particulate Materials; 2015 May 17–20; San Diego, CA. MPIF; 2015.
13.
Karwan-BaczewskaJ.Processing and properties of distaloy Sa sintered alloys with boron and carbon. Arch Metall Mater. 2015;60(1):41–45.
14.
MarucciM, LawleyA, CaustonR, . Effect of small additions of boron on the mechanical properties and hardenability of sintered P/M steels. Powder Metall. 2011;46(2):171–174.
15.
GélinasS, RousseauJ-N, BlaisC.Solidification structures in low-alloyed powder metallurgy steels obtained through permanent liquid phase sintering using a master alloy containing boron. Mater Perform Charact. 2020;9(4):452–469.
16.
SkałońM, HebdaM, SulikowskaK, . Influence of FeNiMnSiB master alloy on the structure and mechanical properties of P/M AISI 316L. Mater Design. 2016;108:462–469.
17.
CastroF, SainzS, VeigaA, . The master alloy concept and its consequences. In: DonaldsonI, MaresNT, editors. International Conference on Powder Metallurgy & Particulate Materials; 2012 Jun 10–13; Nashville, TN. MPIF; 2012.
18.
GermanRM.Sintering: from empirical observations to scientific principles. Oxford (UK): Butterworth-Heinemann Elsevier; 2014.
19.
MPIF. Standard test methods for metal powders & powder metallurgy (PM) products. Princeton (NJ): Metal Powder Industries Federation.
20.
SarasolaM, TojalC, CastroF.Study of boron behaviour during sintering of FeMo/B/C alloys to near full density. Euro PM2004; 2004 Oct 17–21; Vienna. EPMA; 2004.
21.
SarasolaM, Gómez-AceboT, CastroF.Liquid generation during sintering of Fe–3.5%Mo powder compacts with elemental boron additions. Acta Mater. 2004;52(15):4615–4622.
22.
SarasolaM, Gómez-AceboT, CastroF.Microstructural development during liquid phase sintering of Fe and Fe–Mo alloys containing elemental boron additions. Powder Metall. 2005;48(1):59–67.
23.
GélinasS, LaraméeG, BlaisC.Artificial intelligence applied to the development and characterization of PM components. Int J Powder Metall. 2021;57(4):37–52.
24.
CastroF, SainzS, MartinezV, . Sinterability, hardenabilility and mechanical properties of Mn-containing PM steels through the Use of a specially designed Fe-Mn-C master alloy. In: GasbarreWR, von ArxJW, editors. International Conference on Powder Metallurgy & Particulate Materials; 2006 Jun 18–21; San Diego, CA. MPIF; 2006.
25.
RoglP.Boron – carbon – iron. In: EffenbergG, IlyenkoS, editors. Landolt-Börnstein – group IV physical chemistry 11D1 – iron systems, part 1. Berlin: Springer; 2008. p. 349–378.
26.
MomeniM, GierlC, DanningerH, . Thermoanalytical sintering studies of Fe–C admixed with ferroboron performed in different atmospheres. Powder Metall. 2012;55(1):54–64.
27.
WuM-W, FanY-C, HuangH-Y, . Liquid phase sintering of boron-containing powder metallurgy steel with chromium and carbon. Metall Mater Trans A. 2015;46(11):5285–5295.
28.
MolinariA, GialanellaS, StraffeliniG, . Dilatometry study of the sintering behavior of boron-alloyed Fe-1.5 pct Mo powder. Metall Mater Trans A. 2000;31(6):1497–1506.
