Process induced multi-layered Titanium – Boron carbide composites via additive manufacturing
Graphical Abstract
Introduction
Over the past three decades, several Titanium Matrix Composites (TMCs) have been evaluated for various aerospace applications, specifically the engine and airframe components. Their high specific strength/stiffness along with excellent wear and heat resistance make them ideal candidates for such applications [1], [2]. For instance, titanium aluminide based TMCs have been shown to possess remarkable high-temperature abilities, up to 760 °C, while offering nearly 50% weight savings compared to the nickel-based superalloys [2], [3]. A wide variety of ceramic particles like TiB, TiC, TiN, SiC, TiB2, Graphene, CNTs, La2O3, etc. have been used for reinforcing the titanium matrix [2], [4], [5], [6], [7]. Among these, fine TiB whiskers and ultra-fine TiC particles have been identified as most suitable candidates due to their excellent chemical compatibility with titanium [8], [9]. Many conventional manufacturing techniques such as powder metallurgy, ingot castings, and melt spinning have been employed in the past for the fabrication of such TMCs [10], [11], [12], [13]. However, complexities like non-uniform distribution/agglomeration of the reinforcement particles, long processing times, substantial energy consumptions and the need for post processing make their implementation less industrially viable [14]. In light of this, additive manufacturing (AM) techniques, due to their high cost/energy efficiencies, extremely high process control, and rapid solidification rates, can be sought as an attractive alternative [15], [16].
In-situ TMCs are a class of TMCs wherein the reinforcements are synthesized during the fabrication process via chemical reaction between the titanium and the feedstock elements like boron, carbon, and nitrogen [2]. In-situ composites are known to perform better than ex-situ composites due to the excellent interfacial coherent and chemical bonding between matrix and the ceramic phase, good thermodynamic stability of the reaction product, and finer scale distribution of the reinforcements within the metal matrix [17]. These advantages can be well exploited using laser additive manufacturing [18], [19], [20], [21]. Laser additive manufacturing also opens up the avenue to process functionally graded near-net shape composites, involving a gradation in the volume fraction of the in-situ reinforcement phase(s) with site specific properties; something very difficult to achieve with conventional manufacturing [22], [23].
A large number of studies have focused on the laser additive manufacturing of Ti-TiC, Ti-TiB, and other Ti-matrix composites using powder blends of Ti with B [24], [25], [26], [27], TiB2 [28], [29], [30], [31], TiC [22], [32], [33], N2 gas [34] and have been largely successful in obtaining near-net-shapes with excellent mechanical properties. While these studies mainly focused on in-situ synthesis of single type of reinforcement particles (TiC, TiB, TiB2, or TiN), Zhang et. al for the first time, have demonstrated the in-situ formation of multiple reinforcement particles by employing B4C as a starting material [18]. The injected B4C particles serve as a stock source for B and C, which upon dissolving, react with titanium in the laser melt pool forming ceramic phases like Ti2C, TiB, TiB2, TiC, etc. [35], [36], [37], [38]. However, the prediction of the type of ceramic phase evolved based on the initial concentration/loading fraction is not straightforward due to dynamic/non-equilibrium conditions prevailing in the laser melt-pool. For instance, Kühnle et al. in their study on Ti-28 (wt%) B4C, had reported to observe Ti2C and TiB phases [35], while in our previous study on similar composition, TiC and TiB phases with negligible amounts of TiB2 were observed [38]. On the other hand, Pouzet et al. have shown the formation of same precipitates, TiB and TiC, for a lower loading fraction (3 wt%) of B4C particles [36]. The melt-pool characteristics associated with the type of AM process employed and associated thermokinetics, the kind of feedstock material used, and the initial loading fraction can be considered critical in determining the final microstructure. However, AM of in-situ TMCs is still surrounded by uncertainty and besides, the literature lacks in detailed microstructural characterization and holistic understanding of the sequence of formation of ceramic phases during the fabrication process. The primary aim of this study is to investigate the microstructural evolution in a LENS (a direct laser deposition technique) processed TMC loaded with 35 wt% B4C. Additionally, wear behavior and mechanisms were also investigated for the alloy.
Section snippets
Laser engineered net shaping (LENS)
Ti (> 99.4% purity, procured from Alfa Aesar) and B4C (> 99% purity, procured from MilliPORe SiGMa) powders were milled in Pulverisette-5 planetary ball mill (Frisch, Germany) with WC vials and balls (diameter = 10 mm) for 8 h. The powders were mixed in 65:35 (Ti: B4C) weight ratio and were milled at 250 RPM with 10:1 ball to powder ratio. Argon gas was purged at regular intervals to maintain the dry inert atmosphere. The milling was interrupted for 30 min after every 1 h. to prevent heating up
Powder characterization
SEM analysis has been performed on pure Ti and B4C powders in order to evaluate the average size and morphology. The low magnification SEM secondary electron images for pure-Ti and pure-B4C powders are shown in Fig.1(a) and 1(b), respectively. Similarly, the high magnification images are represented in Fig. 1(d) and 1(e), respectively. The Ti powders appeared to be spherical in shape, while the B4C powders appeared faceted and highly irregular. However, both the powders exhibited nearly
Summary and conclusions
LENS processed Ti-35 wt% B4C composites with three distinct laser powers (300, 500, and 700 W), exhibited a novel periodic multi-layered structure with two distinctly different alternating layers. SEM-EBSD coupled with EDS and TEM were utilized to identify the various phases constituting these layers. One of the layers predominantly consisted of TiB2 and inter-dendritic TiC phases, while the other alternating layer exhibited a rather complex microstructure, comprising of TiB, TiC, partially
CRediT authorship contribution statement
M.S.K.K.Y. Nartu: Formal analysis, Investigation, Writing - original draft. M. Pole: Formal analysis, Investigation, Writing - review & editing. S.A. Mantri: Formal analysis, Investigation, Writing - review & editing. R.S. Haridas: Formal analysis, Investigation. T.W. Scharf: Formal analysis, Investigation, Writing - review & editing B. McWilliams: Funding acquisition, Supervision. K. Cho: Funding acquisition, Supervision. S. Mukherjee: Resources. N.B. Dahotre: Funding acquisition, Resources,
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
This research has been supported by U.S. Army Research Laboratory (ARL) (cooperative agreement with the University of North Texas) under the grant W911NF-19-2-0011. The authors acknowledge the infrastructure and support of Center for Agile & Adaptive and Additive Manufacturing (CAAAM) funded through State of Texas Appropriation #190405-105-805008-220 at the University of North Texas. The authors would also like to acknowledge Materials Research Facility (MRF) for access to advanced
References (61)
- et al.
Design of powder metallurgy titanium alloys and composites
Mater. Sci. Eng. A
(2006) - et al.
Titanium metal matrix composites: an overview
Compos. Part A Appl. Sci. Manuf.
(2019) - et al.
Synthesis and characterization of nano-sized Al2O3 particle reinforced ZA-27 metal matrix composites
Procedia Mater. Sci.
(2015) - et al.
Production and mechanical properties of nano SiC particle reinforced Ti–6Al–4V matrix composite
Trans. Nonferrous Met. Soc. China
(2017) - et al.
Hybrid effect of TiBw and TiCp on tensile properties of in situ titanium matrix composites
J. Alloy. Compd.
(2008) - et al.
The influences of trace TiB and TiC on microstructure refinement and mechanical properties of in situ synthesized Ti matrix composite
Compos. Part B Eng.
(2012) - et al.
Effect of volume fraction of reinforcement on room temperature tensile property of in situ (TiB+ TiC)/Ti matrix composites
Mater. Des.
(2006) Titanium metal matrix composites by powder metallurgy (PM) routes
- et al.
Recent developments and opportunities in additive manufacturing of titanium-based matrix composites: a review
Int. J. Mach. Tools Manuf.
(2018) - et al.
Characterization of (TiB+ TiC)/TC4 in situ titanium matrix composites prepared by laser direct deposition
J. Mater. Process. Technol.
(2011)
Microstructure growth behavior and its evolution mechanism during laser additive manufacture of in-situ reinforced (TiB+ TiC)/Ti composite
J. Alloy. Compd.
Microstructure evolution and mechanical properties of selective laser melted bulk-form titanium matrix nanocomposites with minor B4C additions
Mater. Des.
Fabrication of functionally graded TiC/Ti composites by Laser Engineered Net Shaping
Scr. Mater.
Machining of functionally graded Ti6Al4V/WC produced by directed energy deposition
Addit. Manuf.
Direct laser deposition of in situ Ti–6Al–4V–TiB composites
Mater. Sci. Eng. A
Laser deposition-additive manufacturing of TiB-Ti composites with novel three-dimensional quasi-continuous network microstructure: effects on strengthening and toughening
Compos. Part B Eng.
Selective laser melting of in situ titanium–titanium boride composites: processing, microstructure and mechanical properties
Acta Mater.
Direct laser fabrication of Ti6Al4V/TiB
J. Mater. Process. Technol.
Mechanical behavior of porous commercially pure Ti and Ti–TiB composite materials manufactured by selective laser melting
Mater. Sci. Eng. A
Wear resistance of laser-deposited boride reinforced Ti-Nb–Zr–Ta alloy composites for orthopedic implants
Mater. Sci. Eng. C
Nanocrystalline TiC reinforced Ti matrix bulk-form nanocomposites by Selective Laser Melting (SLM): densification, growth mechanism and wear behavior
Compos. Sci. Technol.
Characterization of laser powder deposited Ti–TiC composites and functional gradient materials
J. Mater. Process. Technol.
In situ nitrided titanium alloys: microstructural evolution during solidification and wear
Acta Mater.
In-situ formation of titanium boride and titanium carbide by Selective Laser Melting
Phys. Procedia
Additive layer manufacturing of titanium matrix composites using the direct metal deposition laser process
Mater. Sci. Eng. A
Microstructure and mechanical properties of (TiB+TiC)/Ti composites fabricated in situ via selective laser melting of Ti and B4C powders
Addit. Manuf.
In situ reactions during direct laser deposition of Ti-B4C composites
Scr. Mater.
Wear and mechanical properties of novel (CuCrFeTiZn)100-xPbx high entropy alloy composite via mechanical alloying and spark plasma sintering
Wear
Structure and morphology evolution during mechanical alloying of Ti-Al-Si powder systems
J. Alloy. Compd.
Phase evolution during early stages of mechanical alloying of Cu-13 wt% Al powder mixtures in a high-energy ball mill
J. Alloy. Compd.
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