Titanium matrix composite lattice structures

Moongkhamklang, Pimsiree; Elzey, D. M.; Wadley, H.N.G.

doi:10.1016/j.compositesa.2007.11.007

Cited by 49 publications

(31 citation statements)

References 42 publications

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“…These structures exhibit an outstanding combination of low density, high strength and stiffness, and good damage tolerance. [18] To date, production methods for microarchitectured titanium have focused on replication precision casting, [19,20] sintering of stacked wire arrays, [21] as well as selective electron beam, [22][23][24] or laser [25] sintering of Ti powders.Recently, we introduced a new method for creating 3D microarchitectured Ti structures that combines: [26] (i) direct ink writing (DIW) of planar lattices composed of two layers of orthogonally oriented, patterned TiH 2 filament arrays, followed by (ii) rolling of these pliable lattices into scrolls, or folding into complex three-dimensional shapes, and finally (iii) heat-treating to reduce the hydride to metallic titanium. This new method is characterized by its simplicity, high shape versatility, and ability to control local geometry, as well as scalability to larger structures.…”

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Microstructure and Mechanical Properties of Reticulated Titanium Scrolls

et al. 2011

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Titanium and its alloys find widespread use in skeletal implants and biomedical devices (e.g., stents and orthodontic applications) owing to their excellent corrosion resistance, bio-compatibility, static and fatigue strength, and lack of magnetism (an important property for magnetic imaging). [1] Microporous titanium provides two additional advantages for implant applications: first, it reduces the stiffness of the material, thus reducing stress shielding, [2,3] and, second, it improves implant anchorage by allowing bone ingrowth. [4][5][6] To date, powder metallurgy approaches have been widely used to create porous Ti structures, through partial sintering, [7][8][9] inclusion of pore formers, [10][11][12][13] expansion of pores pressurized with argon or hydrogen gas, [14,15] or replication of cellular polymers. [16,17] Embrittlement often arises during processing due to the strong chemical affinity of titanium at elevated temperature with atmospheric oxygen, carbon, and nitrogen. Alternate efforts have focused on producing microarchitectured titanium, composed of lattice or truss structures with struts arranged periodically in space. These structures exhibit an outstanding combination of low density, high strength and stiffness, and good damage tolerance. [18] To date, production methods for microarchitectured titanium have focused on replication precision casting, [19,20] sintering of stacked wire arrays, [21] as well as selective electron beam, [22][23][24] or laser [25] sintering of Ti powders.Recently, we introduced a new method for creating 3D microarchitectured Ti structures that combines: [26] (i) direct ink writing (DIW) of planar lattices composed of two layers of orthogonally oriented, patterned TiH 2 filament arrays, followed by (ii) rolling of these pliable lattices into scrolls, or folding into complex three-dimensional shapes, and finally (iii) heat-treating to reduce the hydride to metallic titanium. This new method is characterized by its simplicity, high shape versatility, and ability to control local geometry, as well as scalability to larger structures. [26] Here, we use this novel COMMUNICATION[*] Prof.

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Microstructure and Mechanical Properties of Reticulated Titanium Scrolls

et al. 2011

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“…[35] The measured diffusion bonding coefficient, b, of the Ti-6Al-4V lattice was 0.64 and so after diffusion bonding, the lattice had a relative density r ¼ 15.3%. Sandwich panel test structures were made by vacuum brazing the Ti-6Al-4V lattices to 2 mm thick Ti-6Al-4V face sheets using TiCuNi-60 1 paste braze alloy (Lucas-Milhaupt Inc., Cudahy, WI).…”

Section: Methodsmentioning

confidence: 99%

“…It is similar to a method recently proposed for the making of cellular materials from titanium coated SiC monofilaments. [35] We show that the compressive strength of these titanium structures is double that of equivalent steel structures making them well suited for situations whereTitanium sandwich panels with cellular cores of a uniform 1-5 mm diameter open cell size are well suited for impact energy absorption and cross flow heat exchange applications. Periodic cellular structures (lattices) made from high specific strength, high temperature alloys are preferred for these multifunctional uses.…”

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Titanium Alloy Lattice Structures with Millimeter Scale Cell Sizes

Moongkhamklang

Wadley

2010

Adv Eng Mater

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Cellular metals with stochastic cell structures (foams) [1] and related materials with periodic (lattice) cell topologies [2] have attracted significant interest because of their multifunctionality. [3] When configured as the core of a sandwich panel, they provide efficient structural load support during bending [4][5][6] while also enabling other functions such as cross flow heat exchange, [7][8][9] acoustic damping, [10,11] and impact energy absorption. [12][13][14] The earliest foams were made from easily cast alloys based upon aluminum and copper [15,16] but recent developments are leading to the emergence of materials made from steels and other higher strength alloys. [17][18][19] While foam structures with either open or closed cell topologies (and occasionally with both) are relatively easily made with a small (millimeter and even submillimeter) cell size, [20] they deform by strut bending and are therefore weak. [21] Periodic structures with lattice or honeycomb cores have been shown to offer much higher specific strengths because strut stretching dominates their response to stress. [22,23] Deshpande and Fleck [24] have shown that the specific strength of a stretch dominated lattice structure usually depends upon the specific strength of the material used to make it, the relative density and a geometric factor that measures the efficiency with which the lattice supports stress. Triangulated structures with the (tetrahedral) octet truss structure [25] (the pyramidal) lattice block arrangement of trusses, [26] and 3D kagome structures [27] are the most efficient topologies for load support. They can be fabricated by investment casting [28][29][30] and by sheet stamping/forming combined with either spot welding, [31] brazing, [32] or bonding. [33] However, it is difficult to fabricate low density versions of these structures with cell diameters below 10 mm.Small cell sizes are of interest for compact heat exchange and for impact mitigation where they then provide a more uniform deformation response. Small cell size periodic structures can be made from metal wires by laying up 2D weaves or 0/90 collinear wire arrays and brazing. [34] The mechanical response of structures made this way from stainless steels have been analyzed in compression, shear, and in bending [5] and shown to provide only slightly reduced strengths compared to optimal topologies. The best of these stainless steel structures give compressive strengths of 10-20 MPa at a density of 0.5 Mg m À3 .Here, we describe a diffusion bonding process that has been developed for making small cell size collinear lattices from Ti-6Al-4V wires of much higher specific strength than stainless steel. It is similar to a method recently proposed for the making of cellular materials from titanium coated SiC monofilaments. [35] We show that the compressive strength of these titanium structures is double that of equivalent steel structures making them well suited for situations whereTitanium sandwich panels with cellular cores of a uniform 1-5 mm diameter open c...

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“…Some recent studies have reported the static performance of composite sandwich cores. These include an investigation of the compressive response of Z-pinned reinforced foam cores in [Marasco et al 2006], the compressive and shear response of carbon fibre square honeycomb cores in [Russell et al 2008], the compressive response of carbon fibre pyramidal truss cores in [Finnegan et al 2007] and titanium coated SiC monofilaments such as those investigated in [Moongkhamklang et al 2008]. Experimental and theoretical work on the static properties of composite corrugated cores has also been recently reported in and ].…”

Section: Introductionmentioning

confidence: 99%

Dynamic compressive response of composite corrugated cores

Russell

Malcom

Wadley

et al. 2010

JoMMS

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The dynamic out-of-plane compressive response of E-glass composite corrugated sandwich cores have been measured for impact velocities ranging from quasistatic to 175 ms −1 . Laboratory scale sandwich cores of relative densityρ ≈ 33% were manufactured from 3D woven E-glass and stitched to S2-glass face-sheets via a double line of Kevlar yarn. Two variants of the sandwich cores were investigated: sandwich cores with the empty spaces between the corrugations filled with a PVC foam, and unfilled corrugations. The stresses on the rear faces of the dynamically compressed sandwich cores were measured using a direct impact Kolsky bar. The compression tests on both the corrugated cores and the parent strut wall material confirmed that these relatively high relative density corrugated cores failed by microbuckling of the strut wall material under quasistatic loading. Moreover, the foam filling did not have any significant effect on the measured responses. The peak stresses of both the strut wall material and corrugated cores increased approximately linearly with strain rate for applied strain rates less than about 4000 s −1 . This increase was attributed to the strain rate sensitivity of the composite matrix material that stabilised the microbuckling failure mode of the E-glass composite. At higher applied strain rates the response was reasonably rate insensitive with compressive crushing of the glass fibres being the dominant failure mode. A simple model utilising the measured dynamic properties of the strut wall material accurately predicts the measured peak strengths of the filled and unfilled corrugated cores.

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Titanium matrix composite lattice structures

Cited by 49 publications

References 42 publications

Microstructure and Mechanical Properties of Reticulated Titanium Scrolls

Microstructure and Mechanical Properties of Reticulated Titanium Scrolls

Titanium Alloy Lattice Structures with Millimeter Scale Cell Sizes

Dynamic compressive response of composite corrugated cores

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