阅读说明：本技术 增强的超塑成形和扩散结合的结构 (Enhanced superplastic forming and diffusion bonding structures ) 是由 C·瓦塞尔 于 2020-09-24 设计创作，主要内容包括：本发明的名称是增强的超塑成形和扩散结合的结构。由超塑性材料形成外面板,其包括钛的外蒙皮以适应特超音速飞行期间施加在特超音速运输载具上的高热应力。该外蒙皮被固定到下面的增强骨架结构上,所述增强骨架结构由可超塑成形的增强(SFR)层组成,例如钛、锆和钼(TZM)合金,当该外蒙皮被加热至超过1200华氏度的温度时该增强层支撑该外蒙皮。外面板包括单独的内蒙皮,该内蒙皮被配置用于附接到框架构件,诸如特超音速运输载具的肋、纵梁或翼梁。多单元芯被夹在外蒙皮和内蒙皮之间,以赋予外面板拉伸和压缩强度。在一种公开的方法中,该芯是超塑成形的并且扩散结合到外蒙皮和内蒙皮。(The invention provides a structure with enhanced superplastic forming and diffusion bonding. The outer panel is formed of a superplastic material, which includes an outer skin of titanium to accommodate the high thermal stresses imposed on the hypersonic transport vehicle during hypersonic flight. The outer skin is secured to an underlying reinforcing skeletal structure composed of Superplastically Formable Reinforcing (SFR) layers, such as a titanium, zirconium, and molybdenum (TZM) alloy, that support the outer skin when the outer skin is heated to temperatures in excess of 1200 degrees fahrenheit. The outer panel includes a separate inner skin configured for attachment to a frame member, such as a rib, stringer, or spar of a hypersonic transport vehicle. The multi-cell core is sandwiched between an outer skin and an inner skin to impart tensile and compressive strength to the outer panel. In one disclosed method, the core is superplastic formed and diffusion bonded to the outer and inner skins.)

1. An outer panel (10) for a transport vehicle (20), the outer panel comprising:

an outer skin (12) configured for atmospheric exposure;

an inner skin (14) configured for attachment to a structural frame member of the transport vehicle (20);

a multi-cell core (16) sandwiched between the outer skin (12) and the inner skin (14); and

a Superplastic Formable Reinforcement (SFR) layer (18) underlying the outer skin (12) and supporting the outer skin (12),

wherein the multi-cell core (16) is superplastic formed and diffusion bonded to the outer and inner skins (12), (14).

2. The outer panel (10) of claim 1, wherein all components (12), (14), (16) except the SFR layer (18) are formed of a titanium alloy.

3. The skin (10) of claim 1 wherein the SFR layer (18) is formed from (a) a superplastic formable alloy consisting of titanium, zirconium, and molybdenum (TZM) or (b) a superplastic formable alloy consisting of Incoloy 909.

4. The outer panel (10) of claim 1, wherein the SFR layer (18) includes a skeletal structure that is located below 20% to 80% of the outer skin (12).

5. The exterior panel (10) of any of claims 1-4, wherein the SFR layer (18) is configured to reinforce the exterior skin (12) at temperatures in a range greater than 1200 degrees Fahrenheit.

6. The outer panel (10) of any of claims 1-5, wherein the SFR layer (18) is 80% to 150% of the thickness of the outer skin (12).

7. A transport vehicle (20) having at least one outer panel (10) comprising:

an outer skin (12) configured for atmospheric exposure;

an inner skin (14) configured for attachment to a structural frame member of the transport vehicle (20);

a multi-cell core (16) configured to impart tensile and compressive strength to the outer panel (10), the multi-cell core (16) being sandwiched between the outer skin (12) and the inner skin (14); and

an SFR layer (18) below the outer skin and supporting the outer skin when a temperature on the outer skin exceeds a predetermined threshold temperature;

wherein the multi-cell core (16) is superplastic formed and diffusion bonded to the outer and inner skins (12), (14).

8. The transport vehicle (20) according to claim 7, wherein the transport vehicle is a hypersonic vehicle having a plurality of outer panels (10), and wherein each outer panel (10) is welded to at least one other outer panel (10).

9. The transport vehicle (20) of claim 7, wherein each SFR layer (18) of each of the plurality of outer panels (10) comprises a SFR layer (18), the SFR layer (18) diffusion bonded to the outer skin (12) to reinforce the outer skin (12) at temperatures above 1200 degrees Fahrenheit.

10. The transport vehicle (20) of any of claims 7-9, wherein the SFR layer (18) is formed from (a) TZM material or (b) Incoloy 909.

11. A method of manufacturing an exterior panel (10) for a transport vehicle (20), the method comprising:

providing an outer skin (12) of superplastic material configured for atmospheric exposure;

providing a SFR layer (18) secured adjacent the outer skin (12);

providing an inner skin (14) of a superplastic material, the inner skin (14) being configured for attachment to a structural frame member of the transport vehicle (20);

providing at least one pair of core sheets (30, 32) of superplastic material for forming a multi-cell core (16) between the outer skin (12) and the inner skin (14); then the

-fixing the SFR layer (18) to the outer skin (12);

-bonding the pair of core sheets (30, 32) together by intermittent seam welding arranged in a predetermined pattern, securing an expansion tube (50) on one edge of the sheets (30, 32), and then applying a continuous weld around the edge of the sheets (30, 32); and

-installing the outer skin (12) and the inner skin (14) together with the core sheets (30, 32) into a pressure containing device (60), -supplying an inert gas into the expansion tube (50) to superplastically form and diffusion bond the skins (12, 14) and core sheets (30, 32) to form a multi-cell core (16) which is integrally bonded to the outer and inner skins (12, 14).

12. The method of claim 11, wherein the SFR layer (18) is configured to support the outer skin (12) when a temperature of the outer skin (12) exceeds a predetermined threshold.

13. The method of claim 11 wherein the SFR layer (18) is formed from (a) a TZM material or (b) an Incoloy 909.

14. The method of claim 11, wherein the SFR layer (18) is 80% to 150% of the thickness of the outer skin (12).

15. The method of claim 11, wherein the SFR layer (18) is located below 20% to 80% of the outer skin (12).

16. The method of claim 11, wherein the SFR layer (18) comprises a skeletal structure beneath the outer skin (12).

17. The method of any of claims 11-16, wherein the SFR layer (18) supports the outer skin (12) when the temperature of the outer skin (12) exceeds 1200 degrees fahrenheit.

Technical Field

The present disclosure relates to a superplastic forming and diffusion bonding (SPF/DB) sandwich structure for aerospace applications.

Background

Thermal loads imposed on the exterior surfaces of high speed aerospace transportation vehicles place significant and continuing demands on improved thermal management strategies.

Outer structures formed of titanium alloys are known to be effective for accommodating high heat flux environments at supersonic speeds. However, for super speed (hypersonic speed), additional thermal compensation mechanisms are sought. Tiles have been used in spacecraft, particularly to manage the thermal load when returning from space to the atmosphere. Nickel alloys have also been used in some structures. However, conventional nickel alloys have proven to be more heavily used and more expensive in terms of their respective structural configurations and fuel requirements. Previous thermal protection for hypersonic aircraft has not been reusable, limiting its usefulness in commercial applications.

Therefore, there is a need for a cheaper structure that can efficiently accommodate temperatures at super sonic speeds.

Disclosure of Invention

According to one aspect of the present disclosure, an exterior panel for a transport vehicle includes an exterior skin configured for atmospheric exposure and an interior skin configured for attachment to structural frame members of the transport vehicle. A multi-cell core is sandwiched between the outer skin and the inner skin, and a super-formed reinforcement (SFR) layer underlies and supports the outer skin. The multi-cell core is superplastic formed and diffusion bonded to the outer skin and the inner skin.

According to another aspect of the present disclosure, a transport vehicle includes at least one outer panel having an outer skin configured for atmospheric exposure. The outer panel includes an inner skin configured for attachment to a structural frame member of a transport vehicle. The multi-cell core is sandwiched between an outer skin and an inner skin to impart tensile and compressive strength to the outer panel, and the SFR layer is located below the outer skin. The multi-cell core is superplastic formed and diffusion bonded to the outer skin and the inner skin.

According to another aspect of the present disclosure, a method of manufacturing an exterior panel for a transport vehicle includes providing an exterior skin of a superplastic material configured for atmospheric exposure and providing an SFR layer underlying and supporting the exterior skin. The method also includes providing an inner skin of superplastic material configured for attachment to a structural frame member of the transport vehicle, and providing at least one pair of laminar layers of superplastic material to form a multi-cell core between the outer skin and the inner skin. Next, the foil layers are bonded together by intermittent seam welding arranged in a predetermined pattern. An expansion tube is secured to one edge of the layer and a continuous fusion weld is applied around the edge of the foil layer. The outer skin and the inner skin are then installed into a pressure containment device along with the laminate layer, and an inert gas is supplied into the inflation tube to superplastically form and diffusion bond (SPF/DB) the skin and layer to form a multi-cell core integrally bonded to the outer skin and the inner skin. In the complete SPF/DB structure, the SFR layer underlies and reinforces the outer skin.

The features, functions, and advantages disclosed herein may be achieved in the examples presented herein or may be provided by other variations, the details of which may be better understood with reference to the following description and drawings.

Brief Description of Drawings

Fig. 1 is a perspective view of one example of an outer panel for use as an aerodynamically exposed surface of a hypersonic transport vehicle constructed in accordance with the present disclosure.

FIG. 2 is a perspective view of one type of hypersonic transport vehicle that may employ the outer panel of FIG. 1.

Fig. 2A is an enlarged view of the inset portion of fig. 2, schematically depicting the application of a plurality of outer panels on a transport vehicle, each outer panel including a Superplastic Formable Reinforcement (SFR) layer (shown in phantom) configured to support an outer skin of the outer panel, according to one example of the present disclosure.

Fig. 3 is an exploded perspective view of the assembly of the outer panel of fig. 1 as it would appear during the initial manufacturing steps, including the outer skin and the inner skin with the upper and lower core sheets (core sheets) sandwiched between the skins and depicting the SFR layers beneath and supporting the outer skin.

FIG. 4 is a side cross-sectional view of a forming fixture incorporating the components of FIG. 3 during manufacture of an outer panel.

Fig. 5 is a schematic perspective view of how a core sheet may behave during its expansion during manufacture of an outer panel.

Fig. 6 is a perspective view of the outer panel including the SFR layers just after manufacture, this view showing a multi-cell core formed from upper and lower core sheets that have been fully expanded between the outer skin and the inner skin.

Fig. 7 depicts a forming press for the fixture of fig. 4 to accommodate the superplastic forming and diffusion bonding process to manufacture the outer panel of the present disclosure.

Fig. 8 is a perspective view of another example of an SFR layer having a different geometric pattern than the SFR layer of fig. 1.

Fig. 9 shows a sequence of method steps for manufacturing the exemplary exterior panel of fig. 1.

The reference figures are not necessarily to scale and any disclosed examples are merely schematically illustrated. Aspects of the disclosed examples can be combined with or substituted for one another, and within various systems and environments not shown or described herein. The following detailed description is, therefore, merely exemplary and is not intended to be limiting in application or use.

Detailed Description

The following detailed description includes apparatus and methods for performing the present disclosure. The actual scope of the disclosure is as defined in the appended claims.

Fig. 1 shows an example of an outer panel 10 that may be used as a reusable outer surface of a hypersonic transport vehicle. The exterior panel 10 includes an exterior skin 12, an interior skin 14, and a multi-cell core 16, all of which may be formed of a titanium alloy. Between the multi-cell core 16 and the outer skin 12, a skeletal Superplastic Formable Reinforcement (SFR) layer 18 is secured to the outer skin 12. The SFR layer 18 may be formed from a dissimilar alloy, such as a titanium-zirconium-molybdenum (TZM) alloy. The latter may, for example, consist of at least 99% molybdenum, 0.5% titanium and 0.08% zirconium. In the disclosed example, the SFR layers 18 are designed to reinforce the outer skin 12 whenever and if the atmospheric friction temperature of the outer skin 12 exceeds the functional limit of titanium, i.e., the temperature of the outer skin exceeds a predetermined threshold. In the first disclosed example, the SFR layer 18 includes a straight (rectilinear) skeletal structure that underlies at least the edges and medial portions of the outer skin 12 as shown. The outer skin 12 may begin to lose strength when exposed to temperatures in excess of 1200 ° F. Since the exposed outer skin 12 is subjected to the maximum amount of heat flux generated by the hypersonic travel through the atmosphere, the SFR layers 18, which act as spine or skeletal support structures, are configured to reinforce, i.e., support, the outer skin when the temperature on the outer skin may exceed the material strength limit of titanium. Placing the SFR layer 18 under the outer skin 12 is particularly desirable when using TZM materials, because a TZM that is a metal alloy may experience significant oxidation if the TZM is directly exposed to the atmosphere.

Although the SFR layers 18 may use TZM materials as described in the first disclosed embodiment, other materials that exhibit high strength and tensile properties at significant temperatures may be used in place of the described SFR layers 18 to reinforce the outer skin 12. For example, while heavier, Incoloy 909, which is composed of an iron-nickel-cobalt alloy having a composition of 42% iron, 38% nickel, 13% cobalt and 4.7% niobium, may be used instead.

The described TZM and Incoloy materials are generally referred to herein as Superplastic Formable Reinforcement (SFR) materials because of their respective combinations of high strength, ductility, and tensile properties at elevated temperatures that exceed the functional capabilities of titanium.

Referring now also to fig. 2, an exemplary passenger hypersonic transport vehicle 20 includes a structural frame member including a pair of wings 22 that support the transport vehicle 20 in flight. The transport vehicle 20 includes a fuselage 24, a nose 26, and a thrust nozzle 28 of an engine (not shown) to accommodate traveling at mach 3 to mach 5 velocities at the stratosphere, i.e., at least 100,000 feet in height. Fig. 2A shows the inset portion of fig. 2, depicting one arrangement of a plurality of exterior panels 10 covering and including at least a portion of a wing 22. In the latter, one exemplary orientation of the otherwise hidden skeletal SFR layer 18 may be as shown in fig. 2A. In this case, the inner skin 14 of the outer panel 10 may be welded or otherwise secured to the structural frame member of the transport vehicle 20, i.e., the wing 22. In addition, each outer panel 10 may be welded to one or more adjacent outer panels 10.

Fig. 3 depicts the above-described assembly of the outer skin 10 prior to forming the multi-cell core 16, which includes the outer skin 12, the SFR layer 18 (e.g., composed of one of the above-described TZM or Incoloy 909 materials), and the inner skin 14. As disclosed in the example of fig. 1, the core 16 of the outer panel 10 is formed of a pair of upper and lower core sheets 30, 32 (fig. 3) composed of a superplastic material, such as a titanium alloy. The formation of the core 16 occurs during the superplastic forming and diffusion bonding (SPF/DB) of the core sheets 30, 32 to the outer skin 12, SFR layers 18, and inner skin 14 in a forming press as described below to ensure permanent integration of the core 16 with the outer and inner skins 12, 14. To this end, the upper and lower core sheets 30, 32 are initially welded together along first and second arrays 34, 36 of intermittent seam welds. Intermittent seam welding is essentially spot welding, which creates small vent holes for balancing air pressure during SPF/DB manufacturing. The first array 34 and the second array 36 are orthogonally oriented relative to each other in a predetermined pattern such that application of air pressure between the core sheets 30, 32 will produce a multi-cell core defined by a uniform arrangement of individual cells, as described in further detail below.

Titanium is a material that is both superplastic and suitable for diffusion bonding. Thus, the term "SPF/DB" as used herein refers to a manufacturing process in which solid state bonding of metal surfaces occurs with the application of heat and pressure for a duration sufficient to produce atomic blending at the bonding interface of the bonded components. Thus, the SPF/DB process involves a diffusion process during superplastic expansion, but it is not sufficient to physically melt the joined surfaces. In contrast, fusion bonding or fusion welding, as used herein, refers to the metallurgical joining of metal surfaces by applying sufficient heat to cause the materials to physically melt at their joining interfaces, i.e., to reach a liquid or plastic state when joined together.

Referring now to fig. 4, a fixture 40 may be used to house the components of fig. 3 during the manufacture of the outer panel 10. The fixing means 40 are defined by an upper frame member 42 and a lower frame member 44 for supporting the respective outer and inner skins 12, 14. The upper and lower spacers 46, 48 are used as standoff supports to ensure a predetermined desired spacing between the outer skin 12 and the inner skin 14 reinforced by the SFR layers 18 while the core sheets 30, 32 are converted into the multi-cell core 16 of the outer panel 10 during the high pressure, high temperature SPF/DB manufacturing process. Although the use of standoff supports 46, 48 is shown in the disclosed fixture 40, manufacture without such standoff supports is possible.

Referring now to fig. 5, a perspective cross-sectional view of the upper and lower core sheets 30, 32 illustrates the expansion of the core sheets during manufacture after an expansion tube 50 has been secured to one edge by fusion welding. The peripheries of the core sheets 30, 32 are bonded together, and the inert gas G is supplied at high pressure into the expansion tube 50. Referring now to fig. 6, the pressure of the gas G on the first and second arrays 34, 36 of intermittent seam welds produces a bulging portion 52 of the lower core sheet 32 and a corresponding bulging portion 54 of the upper core sheet 30, and ultimately transforms the core sheets into a fully formed cell structure 52' (fig. 6) of the multi-cell core 16 (fig. 6). Furthermore, it should be understood that the visible outline or dividing line between the components, i.e., the outer skin 12, the SFR layer 18, the inner skin 14, and the upper and lower core sheets 30, 32, all as schematically illustrated in fig. 6, is merely used to describe how the components fit together after the SPF/DB manufacturing process. Indeed, any cross-section taken after manufacture of such an outer panel 10 will not show a visible demarcation line because the components will then be integrally joined together into a unified structure.

With continued reference to fig. 6, it should be appreciated that the intermittent seam welding of each of the first and second arrays 34, 36, the upper outer skin 12 with the reinforcing SFR layer 18, and the lower inner skin 14, define a single unit 52' of the core 16 of the superplastic formed and diffusion bonded outer panel 10. In the example described, the SFR layer may be welded or at least spot welded to the outer skin 12 prior to assembly of the assembly and prior to entry of the inert gas G.

Referring now also to FIG. 7, a pressure containment device, such as a superplastic forming press 60, includes a lower member, such as a containment tank 62, and an upper member, such as a containment tank cover 64, configured to be secured to the containment tank 62. It should be appreciated that the fixture 40 of fig. 4, including the various components described above for the pre-fabricated outer panel 10 (fig. 3), is inserted into a superplastic forming press 60 to manufacture each finished outer panel 10 via the SPF/DB process. For this purpose, an inert gas G (e.g. argon) may be used to pressurize the forming of the outer panel 10, especially if such structure is composed of super plastic flexible material (e.g. the titanium alloys and SFR components described). Other inert gases may also be suitable for use with the above-described assembly.

With continued reference to fig. 7, prior to pressurizing the superplastic forming press 60, the atmosphere is first purged (purge) from the superplastic forming press 60 using a non-corrosive gas (e.g., argon) because the atmosphere may be corrosive at SPF/DB manufacturing temperatures approaching 1700 ° F. To this end, purge and vacuum lines, such as vacuum line 56, lower purge line 58, upper purge line 66, and purge vent 68, are shown schematically as exemplary structures for accommodating pre-production purging. After each instance of SPF/DB manufacture of the outer panel 10 is completed, the finished outer panel 10 (e.g., fig. 1) is removed from the superplastic forming press and trimmed. Thus, fig. 1 depicts the completed, fully finished outer panel 10, i.e., having been removed from the superplastic forming press 60 and the fixture 40, and the expansion tube 50 removed.

It may be noted that during hypersonic flight, the steady state operating temperature of the outer skin 12 of the outer panel 10 made of titanium alloy may be as high as in the range of 1100 to 1200 ° F. The thickness of the outer skin 12 may be in the range of up to about sixty thousandths of an inch, while the SFR layer (18) may be in the range of 80% to 150% of the thickness of the outer skin (12). Further, the SFR layer (18) may be located below at least 20% to 80% of the outer skin (12). The core sheets 30, 32 may have a thickness in the range of 1mm or forty thousandths of an inch, and the thickness of the inner skin 14 may be comparable to or slightly less than the thickness of the outer skin 12. The pressure of the gas G during SPF/DB manufacturing may be in the range between 200-500 psi.

Referring now to fig. 8, an alternative enhanced SFR layer 78 is shown. The SFR layer 78 is formed using an SPF/DB manufacturing process that is similar to the previously described example, i.e., the SFR layer 18 of fig. 1, but may include a plurality of circular holes 80, shown in fig. 8 as but one example.

Referring now to fig. 9, a method of manufacturing an exemplary outer panel 10 (fig. 1) for a transport vehicle 20 (fig. 2) includes a step 150 of providing an outer skin 12 of a superplastic material (e.g., a titanium alloy) configured for atmospheric exposure. The method also provides for securing 152 the SFR layers 18 to the outer skin 12 and providing 154 the inner skin 14. The inner skin is also made of a superplastic material and is configured for attachment to a structural framing member, such as the wing 22 of the transport vehicle 20. The method next includes step 156, where step 156 provides a pair of core sheets 30, 32, also made of a superplastic material, for forming a multi-cell core 16 between the outer skin 12 and the inner skin 14. Next, according to step 158, the core sheets 30, 32 are bonded together by intermittent seam welding arranged in a predetermined pattern, as exemplified by arrays 34 and 36 (FIG. 3).

The expansion tube 50 is next secured to one edge of the core sheets 30, 32, according to step 160, and then a continuous weld is applied around all edges of the layers in step 162. In step 164, the outer skin 12 and the inner skin 14 are inserted into the fixture 40 along with the core sheets 30, 32 and then placed in a pressure containment device, such as a superplastic forming press 60. In step 166, the superplastic forming press 60 is purged and an inert gas G is supplied into the expansion tube 50 to superplastically pressurize the skins and plies to form the multi-cell core 16, the multi-cell core 16 being integrally bonded to the outer and inner skins 12, 14.

As noted above, during the SPF/DB process, pressures of 200 and 500psi may be reached during the superplastic forming of the outer panel 10 described above.

Although only a few examples and method steps have been described herein, this disclosure may admit to other variations and modifications not described or suggested. For example, although not described above, the outer panel 10 may have other multi-cell core configurations, which results in a significantly lighter, simpler, and cheaper structure. For example, in some contemplated examples, the multi-unit core may be formed from only a single core sheet layer. In addition, the outer panel 10 may be manufactured using an inert gas other than argon in the SPF/DB process. Further, it is envisioned that material compositions other than the described TZM and Incoloy materials may be used for the disclosed Superplastic Formable Reinforcement (SFR) layers 18 to support the outer skin 12, such that their high strength and tensile properties remain effective in environments in excess of 1200 degrees fahrenheit. Finally, as can be appreciated by those skilled in the art, several other possible methods not described herein can be envisaged for manufacturing the outer panel 10.

Clause 1: an outer panel for a transport vehicle, the outer panel comprising an outer skin configured for atmospheric exposure; an inner skin configured for attachment to a structural frame member of the transport vehicle; a multi-cell core sandwiched between the outer skin and the inner skin; and a Superplastic Formable Reinforcement (SFR) layer underlying and supporting the outer skin, wherein the multi-cell core is superplastic formed and diffusion bonded to the outer skin and the inner skin.

Clause 2: the outer panel of clause 1, wherein all components except the SFR layer are formed of a titanium alloy.

Clause 3: the outer panel of clauses 1 or 2, wherein the SFR layer is formed from a superplastic formable alloy consisting of titanium, zirconium, and molybdenum (TZM).

Clause 4: the outer panel of clauses 1-3, wherein the SFR layer is formed from a superplastic formable alloy consisting of Incoloy 909.

Clause 5: the exterior panel of clauses 1-4, wherein the SFR layer comprises a skeletal structure that is located below 20% to 80% of the exterior skin.

Clause 6: the exterior panel of clauses 1-5, wherein the SFR layer is configured to reinforce the exterior skin at a temperature in a range greater than 1200 degrees fahrenheit.

Clause 7: the outer panel of clauses 1-6, wherein the SFR layer is 80% to 150% of the thickness of the outer skin.

Clause 8: a transport vehicle having at least one outer panel, the at least one outer panel comprising an outer skin configured for atmospheric exposure; an inner skin configured for attachment to a structural frame member of a transport vehicle; a multi-cell core configured to impart tensile and compressive strength to an outer panel, the multi-cell core sandwiched between the outer skin and the inner skin; and an SFR layer below the outer skin and supporting the outer skin when a temperature on the outer skin exceeds a predetermined threshold temperature; wherein the multi-cell core is superplastic formed and diffusion bonded to the outer skin and the inner skin.

Clause 9: the transport vehicle of clause 8, wherein the transport vehicle is a hypersonic vehicle having a plurality of outer panels, and wherein each outer panel is welded to at least one other outer panel.

Clause 10: the transport vehicle of clause 8 or 9, wherein each SFR layer of each outer panel of the plurality of outer panels comprises a SFR layer diffusion bonded to the outer skin to reinforce the outer skin at temperatures greater than 1200 degrees fahrenheit.

Clause 11: the transport vehicle of clauses 8-10, wherein the SFR layer is formed of a TZM material.

Clause 12: the transport vehicle of clauses 8-11, wherein the SFR layer is formed from Incoloy 909.

Clause 13: a method of manufacturing an exterior panel for a transport vehicle, the method comprising providing an exterior skin of a superplastic material configured for atmospheric exposure; providing an SFR layer secured adjacent the outer skin; providing an inner skin of superplastic material configured for attachment to a structural frame member of a transport vehicle; providing at least one pair of core sheets of superplastic material for forming a multi-cell core between the outer skin and the inner skin; then securing the SFR layer to the outer skin; bonding the pair of core sheets together by intermittent seam welding arranged in a predetermined pattern, securing an expansion tube to one edge of the sheets, and then applying a continuous weld around the edge of the sheets; installing an outer skin and an inner skin together with a core sheet into a pressure containment device, supplying an inert gas into the inflation tube to superplastically form and diffusion bond the skins and the core sheet to form a multi-cell core integrally bonded to the outer skin and the inner skin.

Clause 14: the method of clause 13, wherein the SFR layer is configured to support the outer skin when the temperature of the outer skin exceeds a predetermined threshold.

Clause 15: the method of clause 13 or 14, wherein the SFR layer is formed of a TZM material.

Clause 16: the method of clauses 13-15, wherein the SFR layer is formed from Incoloy 909.

Clause 17: the method of clauses 13-16, wherein the SFR layer is 80% to 150% of the thickness of the outer skin.

Clause 18: the method of clauses 13-17, wherein the SFR layer is located below 20% to 80% of the outer skin.

Clause 19: the method of clauses 13-18, wherein the SFR layer comprises a skeletal structure underlying the outer skin.

Clause 20: the method of clauses 13-19, wherein the SFR layer supports the outer skin when the temperature of the outer skin exceeds 1200 degrees fahrenheit.