Laser additive manufactured high-performance Fe-based composites with unique strengthening structure

doi:10.1016/j.jmst.2020.04.011

Abstract

Abstract:

Steel matrix composites (SMCs), reinforced by ceramic particles, have received a consistent attention in recent years. Using conventional methods to prepare SMCs is generally challenging, and the mechanical properties of conventionally fabricated SMCs are limited. In this study, we successfully fabricated high-performance SMCs by laser powder bed fusion (LPBF) of a composite powder consisting of Fe-based alloy powder and submicron-sized WC particles. The effect of laser energy density on the phase formation, microstructural evolution, overall density and resulting mechanical properties of LPBF-fabricated composites was investigated. The present results show that a novel Fe₂W₄C carbidic network precipitates in the solidified microstructure entailing segregations along the boundaries of cellular sub-grains. The presence of this carbidic network hampers the growth of sub-grains even at elevated temperatures, and hence, stabilizes the grain size though prepared at a broad range of different energy densities. The exact distribution of the Fe₂W₄C carbides depends on the employed laser energy densities, as for instance they are more uniformly distributed at higher energy input. The density of LPBF samples reaches the maximum value of 99.4 % at 150 J/mm³. In this parameter set, high microhardness of ∼753 HV, compression strength of ∼3350 MPa and fracture strain of ∼24.4 % are obtained. The enhanced mechanical properties are ascribed to less metallurgical defects, higher volume fraction of the martensitic phase and increasing pile-up dislocations resulting from the pinning effect by Fe₂W₄C carbide.

Key words: Laser additive manufacturing, Laser powder bed fusion, Steel atrix composite, Microstructures, Mechanical properties

Hongyu Chen, Dongdong Gu, Liang Deng, Tiwen Lu, Uta Kühn, Konrad Kosiba. Laser additive manufactured high-performance Fe-based composites with unique strengthening structure[J]. J. Mater. Sci. Technol., 2021, 89: 242-252.

Figures/Tables 14

Table 1 Chemical compositions of as-used Fe-based alloy powder (wt.%).

Fe	C	Cr	Ni	Mo	Si	Mn	P	S
Balance	0.45	1.35	4.0	0.25	0.25	0.40	≤0.025	≤0.005

Fig. 1. (a) Scanning electron microscope (SEM) images display typical morphologies of the as-prepared composite powder. (b) The magnified SEM image highlights the distribution of WC particle on the surface of particles of the matrix powder. (c, d) The energy-dispersive X-ray spectroscopy (EDS) analysis confirms the submicron-sized particle to be the WC, where the atomic fraction of C is much higher than W probably because of the contamination of C or different sensitivities of W and C to EDS detection during SEM.

Fig. 2. Variation of relative density of LPBF-processed composite samples at different laser energy densities.

Fig. 3. SEM images show typical surface morphologies and the μ-CTs reveal the distribution of pores within LPBF-processed composite samples prepared at various laser energy densities: (a, b) 60 J/mm3; (c, d) 100 J/mm3; (e, f) 150 J/mm3; (g, h) 200 J/mm3.

Fig. 4. (a) XRD pattern of LPBF-fabricated composite samples processed at different laser energy densities. (b) Additional XRD pattern were obtained for the 2θ region where reflections of α-Fe and γ-Fe phases are present (50°-54°).

Table 2 Lattice parameters of austenite and martensite and content of retained-austenite within composite samples processed at different processing parameters.

Sample	Lattice parameters of austenite (Å)	Lattice parameters of martensite (Å)	Content of retained-austenite (vol.%)
60 J/mm³	a = 3.606	a = 2.822, c = 2.931	18.1
100 J/mm³	a = 3.604	a = 2.826, c = 2.935	16.7
150 J/mm³	a = 3.602	a = 2.830, c = 2.933	13.2
200 J/mm³	a = 3.599	a = 2.818, c = 2.926	12.8

Fig. 5. SEM images show etched microstructures of LPBF samples processed at different laser energy densities: (a) 60 J/mm3; (b) 100 J/mm3; (c) 150 J/mm3; (d) 200 J/mm3.

Fig. 6. Magnified SEM images of the cellular structures and related EDX mappings showing the element distribution of C, Fe, W, and Cr. (η = 150 J/mm3).

Fig. 7. (a) Bright-field TEM image of the cellular structure and carbidic network formed along the cell boundaries; (b) the corresponding SAED pattern of the indicated region in (a).

Fig. 8. Schematics illustrate the mechanism of the solidification process during LPBF resulting in the microstructure of the composite material. (a) Composite powder is exposed by the high-energy laser beam (red area). (b) Fe-based matrix and WC particles are completely molten and uniformly dissolved in a liquid. (c) Aside the austenitic Fe-based matrix, Fe2W4C carbides precipitate and form a network. (d) Once the temperature is below the martensite start temperature, Ms, the austenite transforms into martensite until the martensite finish temperature, Mf, is reached.

Fig. 9. Microhardness maps obtained at the lateral surface of samples prepared at different laser energy densities: (a) 60 J/mm3; (b) 100 J/mm3; (c) 150 J/mm3; (d) 200 J/mm3.

Fig. 10. Different indentation morphologies corresponding to different microhardness values of LPBD-fabricated composites prepared at different laser energy densities: (a) 60 J/mm3; (b) 100 J/mm3; (c) 150 J/mm3; (d) 200 J/mm3.

Fig. 11. Engineering compressive stress-strain curves of the LPBF samples prepared at different laser energy densities.

Fig. 12. Typical SEM images taken from the fracture surfaces of compressed specimens fabricated at different laser energy densities: (a) 60 J/mm3; (b) 100 J/mm3; (c) 150 J/mm3; (d) 200 J/mm3.

References 44

[1]	R. Casati, J. Lemke, M. Vedani, , J. Mater. Sci. Technol. 32 (2016) 738-744. DOI URL
[2]	H. Attar, M. Bönisch, M. Calin, L.C. Zhang, S. Scudino, J. Eckert, Acta Mater. 76 (2014) 13-22. DOI URL
[3]	L.C. Zhang, D. Klemm, J. Eckert, Y.L. Hao, T.B. Sercombe, Scr. Mater. 65 (2011) 21-24. DOI URL
[4]	J. Trapp, A.M. Rubenchik, G. Guss, M.J. Matthews, Appl. Mater. Today 9 (2017) 341-349.
[5]	S. Pauly, P. Wang, U. Kühn, K. Kosiba, Addit. Manuf. 22 (2018) 753-757.
[6]	J. Sander, J. Hufenbach, L. Giebeler, H. Wendrock, U. Kühn, J. Eckert, Mater.Des. 89 (2016) 335-341.
[7]	J. Suryawanshi, K.G. Prashanth, S. Scudino, J. Eckert, O. Prakash U. Ramamurty, Acta Mater. 115 (2016) 285-294. DOI URL
[8]	Y.M. Wang, T. Voisin, J.T.McKeown, J.C. Ye, N.P. Calta, Z. Li, Z. Zeng, Y. Zhang,W. Chen, T.T. Roehling, R.T. Ott, M.K. Santala, P.J. Depond, M.J. Matthews, A.V.Hamza, T. Zhu, Nat. Mater. 17 (2018) 63-71. DOI URL
[9]	Y.J. Liu, S.J. Li, L.C. Zhang, Y.L. Hao, T.B. Sercombe, Scr. Mater. 153 (2018) 99-103. DOI URL
[10]	K. Das, T. Bandyopadhyay, S. Das, , J. Mater. Sci. 37 (2002) 3881-3892. DOI URL
[11]	B. AlMangour, D. Grzesiak, J.M. Yang, Mater. Des. 104 (2016) 141-151. DOI URL
[12]	B. AlMangour, D. Grzesiak, J.M. Yang, Mater. Des. 96 (2016) 150-161. DOI URL
[13]	W.Q. Hu, Z. Dong, L.M. Yu, Z.Q. Ma, Y.C. Liu, , J. Mater. Sci. Technol. 36 (2020) 84-90. DOI URL
[14]	Kovalev, A.M. Gurin, Int. J. Heat Mass Tran. 68 (2014) 269-277.
[15]	B. Song, S. Dong, P. Coddet, G. Zhou, S. Ouyang, H. Liao, C. Coddet, J. AlloysCompd. 579 (2013) 415-421.
[16]	N. Kang, W. Ma, L. Heraud, M. El Mansori, F. Li, M. Liu, H. Liao, Addit. Manuf. 22 (2018) 104-110.
[17]	B. AlMangour, D. Grzesiak, J.M. Yang, , J. Mater. Process. Technol. 244 (2017) 344-353. DOI URL
[18]	T. Boegelein, S.N. Dryepondt, A. Pandey, K. Dawson, G.J. Tatlock, Acta Mater. 87 (2015) 201-215. DOI URL
[19]	N. Kang, W.Y. Ma, F.H. Li, H.L. Liao, M. Liu, C. Coddet, Vacuum 154 (2018) 69-74. DOI URL
[20]	J.D. Wang, L.Q. Li, W. Tao, Opt. Laser Technol. 82 (2016) 170-182. DOI URL
[21]	D.J. Liu, L.Q. Li, F.Q. Li, Y.B. Chen, Surf. Coat. Technol. 202 (2008) 1771-1777. DOI URL
[22]	J.M. Howe, Int. Mater. Rev. 38 (1993) 233-256. DOI URL
[23]	S.K. Ghosh, P. Saha, Mater. Des. 32 (2011) 139-145. DOI URL
[24]	H.H. Zhu, L. Lu, J.Y.H. Fuh, Mater. Sci. Eng. A 371 (2004) 170-177. DOI URL
[25]	J.P. Kruth, G. Levy, F. Klocke, T.H.C.Childs, CIRP Ann-Manuf.Technol. 56 (2007) 730-759.
[26]	D.D. Gu, Y.-C. Hagedorn, W.Meiners, G.B. Meng, R.J.S. Batista, K. Wissenbach,R. Poprawe, Acta Mater. 60 (2012) 3849-3860. DOI URL
[27]	K. Arafune, A. Hirata, J. Cryst. Growth 197 (1999) 811-817. DOI URL
[28]	M.L. Zhong, H.Q. Sun, W.J. Liu, X.F. Zhu, J.J. He, Scr. Mater. 53 (2005) 159-164. DOI URL
[29]	J. Suryawanshi, K.G. Prashanth, S. Scudino, J. Eckert, Om Prakash, U.Ramamurty, Acta Mater. 115 (2016) 285-294.
[30]	J.M. Moyer, G.S. Ansell, Metall. Trans. A 6 (1975) 1785-1791. DOI URL
[31]	G. Cacciamani, A. Dinsdale, S. Palumbo, Intermetallics 18 (2010) 1148-1162. DOI URL
[32]	P.P. Yuan, D.D. Gu, D.H. Dai, Mater. Des. 82 (2015) 46-55. DOI URL
[33]	B. AlMangour, D. Grzesiak, J.M. Yang, , J. Alloys Compd. 706 (2017) 409-418. DOI URL
[34]	X. Wu, G. Chen, , J. Mater. Sci. Technol. 15 (1999) 233-238.
[35]	D. Wang, C.H. Song, Y.Q. Yang, Y.C. Bai, Mater. Des. 100 (2016) 291-299. DOI URL
[36]	D.D. Gu, H.Q. Wang, D.H. Dai, P.P. Yuan, W. Meiners, R. Poprawe, Scr. Mater. 96 (2015) 25-28. DOI URL
[37]	T. Niendorf, S. Leuders, A. Riemer, H.A. Richard, T. Tröster, D. Schwarze, Metall.Mater. Trans. B 44 (2013) 794-796.
[38]	Z. Wang, T.A. Palmer, A.M. Beese, Acta Mater. 110 (2016) 226-235. DOI URL
[39]	J.W. Cahn, Acta Metall. Sin. 10 (1962) 789-798.
[40]	P. Borm, F.C. Klaessig, T.D. Landry, B. Moudgil, J. Pauluhn, K. Thomas, R. Trottier, S. Wood, Toxicol. Sci. 90 (2006) 23-32. PMID
[41]	C.C. Koch, R.O. Scattergood, Mater. Res. Lett. 3 (2015) 65-75. DOI URL
[42]	M.J. Holzweissig, A. Taube, F. Brenne, M. Schaper, T. Niendorf, Metall. Mater.Trans. B 46 (2015) 545-549.
[43]	A. Inoue, B.L. Shen, C.T. Chang, Acta Mater. 52 (2004) 4093-4099. DOI URL
[44]	Z. Trojanová, V. Gärtnerová, A. Jäger, A. Námešný, P. M.Chalupová, P. Palček, Lukáč, Compos. Sci. Technol. 69 (2009) 2256-2264.