SITIS Archives - Topic Details
Program:  SBIR
Topic Num:  A10-063 (Army)
Title:  Cast Encapsulation of Unfinished Ceramic Armor Tiles
Research & Technical Areas:  Ground/Sea Vehicles, Materials/Processes

Acquisition Program:  PM Future Combat Systems Brigade Combat Team
  Objective:  The purpose of this proposal is to establish an alternative metal encapsulation mechanism of unfinished ceramic tiles that will provide the Army with a greatly reduced cost option for legacy and future platforms within the current repertoire for armor solutions. This purpose with be accomplished by leveraging existing design, modeling, and newly established manufacturing technology (MANTECH) capabilities against well known established manufacturing practices with large US industrial capacity employing existing metal alloy systems; systems that lack expensive elements, that are not environmentally prohibitive, or are sensitive due to their strategic alloy element acquisition. A low-cost manufacturing process is sought that will directly cast the encapsulated ceramic structure to net/near-net shape and eliminate ceramic tile finishing practices currently required for existing ceramic panel designs.
  Description:  The casting process must produce sound parts where the metal encapsulating structure must be intact, crack-free, and of a structural metal (Mg, Al, Ti, or Fe based alloys). The ceramic tiles must be constrained throughout the process so that they remain in a fixed location in the part throughout the process. Also, the ceramic must not be degraded or damaged by the metal, either by chemical attack or dissolution, thermal shock damage, or residual stress induced fracture. If there is potential for reaction with the metal during the casting process, the manufacturer must detail what steps will be taken to mitigate the reaction and protect the tiles.

  PHASE I: Phase I will require a manufacturer to deliver two 26” x 26” panels of a surrogate design with encapsulated unfinished 3/4" to 1" thick 4" (measured flat to flat) hexagonal ceramic tiles arranged in an A/B stacking sequence with 1/8" spacing between tiles. Tiles must be located within 1/4" and parallel to the metal surface of one side of the panel with a 1" thick cast metal backing on the opposite side of the panel. The cast metal panel side walls must be at least 1/4" thick on all sides. The process must be able to encapsulate the tiles without generating damage in the materials either by chemical attack/dissolution, thermal shock damage, or residual stress fracturing the tiles. The ceramic tiles must remain in a preferred orientation throughout the process, and the manufacturer must address how the tiles will be immobilized during the casting process. Provided by the manufacturer will be x-ray images of the encapsulation showing the location and lack of damage in the intact tiles. Further non destructive evaluation (NDE) of the panels will take place at ARL by phased array technique to verify x-ray analysis. Panels will be ballistically evaluated for qualitative analysis in this phase to inspect and verify metal-ceramic bonding. Key to potential advancement to Phase II is the ability of the manufacturer to: 1) duplicate consistent pannels with required geometries and arrangement of tiles, 2)contain less than 2% porosity(by gas entrapment or internal shrinkage) without the need to hot isostatic press (HIP) the casting, 3)producing pannels without weld repair and straightening, and 4)demonstrate by post ballistic analysis that the metal-ceramic interface remained intact. Ferrous amd titanium based alloys must attain a yield strength of at least 100 ksi, 10% elongation, and Charpy V-notch impact toughness of 20 ft-lbs at room temperature. Aluminum and magnesium based alloys must attain a yield strength of 40 ksi, 7% elongation, and fracture toughness of 25 ksi per root inch at room temperature. Alloy property testing must be done in accordance with ASTM standards and test data must accompany both plates and be provided to the Army Research Lab (ARL)at the time of shipment. All alloys must be gas metal arc weld (GMAW) capable. Metal matrix solutions are not sought with this solicitation.
  PHASE II: Phase II will leverage existing armor designs provided by the Army Research Lab (ARL) to incorporate the manufacturing method from Phase I. The contractor will address scale-up of the process to make parts larger than the 26” x 26” size, and by the end of the Phase II be able to produce and deliver a 2 modules larger than 36” x 36”. Included in this phase is funding for non destructive evaluation (NDE) of cast material (prior to testing) as required in Phase I. Panel geometries and tile selection will be downselected to best support current Army needs at the time that Phase II is awarded. Threat specific testing will be conducted on all panels. Successful Phase II completion is predicated upon passage of the specific threat testing.

  PHASE III: Successful Phase II testing facilitates immediate vehicle integration of demonstrated technology. The manufacturing technology and threat information will be transitioned to both Tank Automotive Research and Development (TARDEC) and Tank Automotive Command (TACOM) for immidiate implementation and integration into existing and future platform engineering efforts.

  References:   1. ASTM E1820 (Fracture Testing of Metals), ASTM E8 (Tensile Testing of Metals), ASTM E23 (Charpy V-Notch Testing)

Keywords:  encapsulation, metal, alloy, ceramic, casting, ferrous, titanium, aluminum, magnesium, manufacturing cost

Questions and Answers:
Q: Q: Is the encapsulation limited to metal materials to encapsulate? Would you consider other materials such as fiber filled polymers?
A: A: "Cast encapsulation" of the SBIR Topic A10-063 is limited to solidification based cast processes of structural (ferrous and non-ferrous) metals and alloys. Therefore, any encapsulation processes utilizing organic polymer filler materials may not be considered.
Q: Will the ceramic tiles either be supplied by ARL or composition specified by ARL?
A: Commercial ceramic tiles may be supplied by the ARL only for the phase I final deliverables if needed. The awardees may also use own choices of ceramic tiles. All awardees are responsible for using own ceramic tiles for all practices. A candidate commercial ceramic tile composition is silicon carbide, aluminum oxide, or boron carbide.
Proposers should consider effectiveness of mass and effectiveness of space as tile encapsulation design criteria.

Q: What is the procedure for requesting tiles from ARL for Phase 1?
A: SBIR A10-063 Phase I awardees will have chances to request tiles from ARL at planned kickoff meetings or through email communications if the awardees choose to use the ARL supplied tiles.
Q: Please clarify what is meant by "hexagonal ceramic tiles arranged in an A/B stacking sequence with 1/8" spacing between tiles."
A: It means hexagonal ceramic tiles are to be laid horizontally at 1/2 height alternatively in vertical position and a spacing between edges (except free edges) of the hexagonal ceramic tiles (i.e., web spacing) is 1/8 inch.
Q: 1) What overall package final thickness is desired as a Phase I deliverable?

2) How many layers of hexagonal tiles in an A-B stacking arrangement are required?

3) For Phase I process development - can smaller more widely available commercially available shapes be used to demonstrate the process?

4) Regarding the hexagonal tiles - how set is the reviewing team on 3/4-1" thick by 4" flat to flat hexagons?

5) Would thinner tiles (3/8-1/2") and more overall composite layers be considered non-responsive?

6) Are there particular ballistically proven alloys of aluminum that are preferred?

7) Could less expensive alternative ceramic materials of similar strength to alumnina or silicon carbide be considered to provide a lower cost per square foot solution?
A: (1) Overall final package thickness can be determined from the Phase I requirements, namely (1) unfinished tile thickness of 3/4" to 1" and (2) 1" thick cast metal backing. Metal cast thicknesses of front-face and back-face of the tiles are to be determined by the proposers.

(2) A minimum of 1 layer.

(3) All novel ideas relevant to the current SBIR topic would be considered. However ranking preferences would be based on meeting or exceeding the topic requirements.

(4) Not sure what the question is asking for. Ceramic tile thickness should be between 3/4" and 1". Dimensions between parallel edges of the hexagonal ceramic tiles should be 4".

(5) All novel ideas relevant to the current SBIR topic would be considered. However ranking preferences would be based on meeting or exceeding the topic requirements.

(6) Aluminum alloy selection is a responsibility of the proposers.

(7) All novel ideas relevant to the current SBIR topic would be considered. However ranking preferences would be based on meeting or exceeding the topic requirements.
Q: Additional information from TPOC for A10-063 (6/17/10):

(Q) How can the topic specification mention alternating layers A & B if only one layer is required per your response in the overall casting?
(A) A/B tile stacking sequence takes place in a x-y plane (i.e., bathroom floor). The 1 layer minimum is a minimum number of tile layer in a z-direction (a through thickness direction of the bathroom floor).

(Q) How can castings be quoted without the overall thickness being specified?
(A) A range of tile thickness (3/4 - 1") is given. Casting and related integration padding thicknesses to the front and back faces of the tiles would be dependent on casting design and associated fabrication techniques to be proposed by proposers.

(Q) How can the proposer determine its costs to respond - tiles, mold size, alloy volume etc.?
(A) A panel width and a panel depth are given. A projected area can be used to estimate a number of tiles needed. A range of ceramic tile thickness is given. A panel thickness would be based on the tile thickness and proposers processing designs., strategy, and technique. Proposers should be able to estimate costs with the given information and their own process design strategy.
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