[雙語翻譯]外文翻譯--激光近凈成形（lens）fe3al類金屬間化合物的微觀組織結(jié)構(gòu)和力學(xué)性質(zhì)（英文）

1、Structure and properties of the Fe3Al-type intermetallic alloy fabricated by laser engineered net shaping (LENS)Tomasz Durejko a, Micha? Zi?tala a, Magda ?azińska a, Stanis?aw Lipiński a, Wojciech Polkowski a, Tomasz Czu

2、jko a,n, Robert A. Varin ba Department of Advanced Materials and Technologies, Military University of Technology, 2 Gen. S. Kaliskiego Street, PL-00-908 Warsaw, Poland b Department of Mechanical and Mechatronics Engineer

3、ing, University of Waterloo, Waterloo, Ont., Canada N2L 3G1a r t i c l e i n f oArticle history:Received 25 July 2015Received in revised form22 September 2015Accepted 20 October 2015 Available online 22 October 2015Keywo

4、rds:IntermetallicsMechanical characterizationAdditive manufacturinga b s t r a c tThe microstructure and mechanical properties of the Fe3Al–0.35Zr–0.1B alloy fabricated by the LaserEngineered Net Shaping (LENS) technique

5、 are presented. Proper technological parameters of the LENSmanufacturing process were selected to obtain elements with a minimal porosity and a satisfactoryshape congruency. The Fe3Al based alloy samples fabricated by th

6、e LENS technique are characterized by ahomogenous chemical composition and diversified grain morphology with columnar grains at the bot-tom and equiaxed grains at the center and edge in the analyzed sample. Phase analysi

7、s showed thepresence of B2 ordered Fe3Al intermetallic and (Fe, Al)2Zr Laves phases. An isothermal annealing carriedout at 450 °C for 50 h led to a phase transformation from a B2 to an equilibrium D03 phase. The Fe3

8、Albased alloy samples with the B2 structure, directly after the LENS process and with the D03 structureafter annealing, exhibited similar yield strength and ultimate tensile strength. However, the presence ofthe D03 stru

9、cture caused a noticeable increase of elongation, especially at elevated temperatures.& 2015 Published by Elsevier B.V.1. IntroductionThe ordered intermetallic alloys based on aluminides of tran-sition metals such as

10、 iron, titanium, nickel, niobium and cobalt canbe potentially applied at temperatures higher than those formodern superalloys while offering better specific mechanicalproperties resulting from their lower densities withi

11、n the range5.4?6.7 g/cm3 [1–5]. Their large content of aluminum (10–20%)allows for the formation of an impervious oxide layer which pre-vents oxidation, sulfidation and carburization at temperaturesapproaching 1000 °

12、;C. The FeAl (B2) and Fe3Al (D03) intermetallicphases possess a high resistance to oxidation, corrosion, wear andcreep above 600 °C [1–8]. Additional creep resistance is achievedby alloying with Mo, Hf, Nb, Zr, and

13、Ta [7–12]. Doping with Zr leadsto the formation of hard (Fe, Al)2Zr Laves phase precipitates whichimprove the mechanical properties at high temperatures [10–14]. These materials are considered for various high-temperatur

14、eapplications, such as furnace fixtures, heat exchanger pipes, cata-lytic converter substrates, automobile and other industrial valvecomponents or parts that work in a molten salt environment[5,15]. As a drawback they ex

15、hibit inferior castability or a largecasting shrinkage [16]. Therefore, sintering or hot extrusion ofelementary powder mixtures were applied for producing the FeAlor Fe3Al alloys [4,17–19]. However, an application of a p

16、owdertechnology to the manufacturing of FeAl or Fe3Al based elementsis associated with a high energy consumption and a low pro-ductivity which result in high production costs [17]. The most suitable technology for proces

17、sing of intermetallic-based alloys is additive manufacturing which, so far, has beenreported in only a few papers [20–22]. Most recently, Durejko et al.[23] reported a successful fabrication of the Fe3Al/SS316L gradedstr

18、ucture obtained by using the laser engineered net shaping(LENS) technology. In the present work authors applied a novel LENS manu-facturing method to produce dense, Fe3Al-based intermetallic al-loys, doped with zirconium

19、 and boron. The LENS technique allowsa simultaneous introduction of alloying elements and control ofstructure and external geometry of manufactured Fe3Al inter-metallic elements, particularly for high temperature applica

20、tions.The present approach is focused on finding a correlation betweenthe LENS process parameters and resulting microstructure. As aconsequence, a selection of the process parameters that producematerials with the best p

21、roperties for their potential application atelevated temperatures is proposed and discussed.Contents lists available at ScienceDirectjournal homepage: www.elsevier.com/locate/mseaMaterials Science & Engineering Ahttp

22、://dx.doi.org/10.1016/j.msea.2015.10.0760921-5093/& 2015 Published by Elsevier B.V.n Corresponding author. Fax: þ48226839445.E-mail address: tczujko@wat.edu.pl (T. Czujko).Materials Science & Engineering A 6

23、50 (2016) 374–381ECD values above 50 μm.3.2. Effect of the LENS process on the porosity of fabricated componentsThe resulting final porosity of a fabricated component is an important microstructural characteristic that d

24、irectly depends on the LENS process parameters. Unfortunately, the final porosity level of a component is a very complex function of various LENS process parameters. An extensive preliminary research on the selection of

25、working parameters has been carried out to fabricate the Fe3Al sample that is characterized by a lowest possible por- osity, absence of cracks and good reproduction of the model's shape. The trials were performed by

26、adjusting the laser powerwithin the range 150–350 W, working table feed within the range 1.5–12 mm/s and powder flow rate within the range 0.35–2.8 g/ min. The powders were deposited on the substrate made of iron Armco w

27、ith a thickness of 11 mm. The fabricated samples had a cylindrical shape with a diameter of 15 mm and a height of 5 mm. Based on the obtained results, the plots of the porosity as a function of the powder flow rate, lase

28、r power and feed rate are shown in Fig. 2. It is observed in Fig. 2a that for the constant laser power of 250 W, a lowering of the powder flow rate leads to a noticeable decrease of the sample porosity to ?0.8%.Fig. 2b c

29、learly shows that the increased laser power reduces porosity quite effectively. Nevertheless, when the laser power value was set up above 300 W, the feed rate had to be increased from 3 to 6 mm/s, in order to maintain a

30、low porosity level. The lowest porosity of 0.8% was obtained for the laser power of 350 W. Finally, a trend between the porosity and working table feed is shown in Fig. 2c. The lowest porosity ?1.1% was measured for the

31、sample that was processed with the following parameters: the working table feed of 1.5 mm/min, powder flow rate of 0.7 g/min and laser power of 250 W. The analysis of the preliminary trial results shows that the porosity

32、 of the LENS fabricated Fe3Al components may be dis- tinctly minimized by a proper selection of the process parameters. This selection should include a combination of a low powder flow rate and working table feed with a

33、simultaneous high laser power.Fig. 1. Morphology of the Fe3Al?0.35Zr?0.1B powder. (a) Overall view, (b) a single porous particle, (c) chemical analysis for single particle and powder particle populationand (d) the distri

34、bution of pores size in particle powder.Table 1The results of chemical analysis for single particle and powder particle population.Chemical composition Single powder particle Powder particlepopulationElement at% wt% at%